added some documentation

+/* Messages used by the Terminal and TerminalManager classes. */
+
+ 
+
+#ifndef MSG_H
+
+#define MSG_H
+
+ 
+
+enum MsgType
+
+{
+
+    CREATE_TERMINAL,
+
+    DELETE_TERMINAL,
+
+    RUN_DIAGNOSTICS,
+
+    PERFORM_SWITCHOVER
+
+};
+
+ 
+
+typedef struct
+
+{
+
+    /*...*/
+
+    int msgType;
+
+    int terminalType;
+
+    int terminalId;
+
+    int otherTerminalId;
+
+    int terminalStatus;
+
+} Msg;
+
+ 
+
+/* Message used to create a terminal. */
+
+typedef struct
+
+{
+
+    Msg header;
+
+}TerminalCreateMsg;
+
+ 
+
+/* Acknowledgement to Terminal Create message. */
+
+typedef struct
+
+{
+
+    Msg header;
+
+} TerminalCreateAck;
+
+ 
+
+/* Terminal Delete message */
+
+typedef struct
+
+{
+
+    Msg header;
+
+} TerminalDeleteMsg;
+
+ 
+
+ 
+
+typedef struct
+
+{
+
+    Msg header;
+
+} RunDiagnosticsMsg;
+
+#endif

+// Messages used by the Terminal and TerminalManager classes.
+
+ 
+
+enum MsgType
+
+{
+
+    CREATE_TERMINAL,
+
+    DELETE_TERMINAL,
+
+    RUN_DIAGNOSTICS,
+
+    PERFORM_SWITCHOVER
+
+};
+
+ 
+
+ 
+
+class Msg
+
+{
+
+    //...
+
+    int msgType;
+
+    int terminalType;
+
+    int terminalId;
+
+    int otherTerminalId;
+
+    int terminalStatus;
+
+ 
+
+public:
+
+    MsgType GetType() const;
+
+    int GetTerminalId() const;
+
+    int GetOtherTerminalId() const;
+
+    int GetTerminalType() const;
+
+};
+
+ 
+
+// Message used to create a terminal
+
+class TerminalCreateMsg : public Msg
+
+{
+
+public:
+
+    int GetTerminalStatus() const;
+
+};
+
+ 
+
+// Acknowledgement to Terminal Create message.
+
+class TerminalCreateAck : public Msg
+
+{
+
+public:
+
+    TerminalCreateAck(int terminalId, int terminalStatus);
+
+};
+
+ 
+
+// Terminal Delete message
+
+class TerminalDeleteMsg : public Msg
+
+{
+
+};

+/* Terminal struct source file. */
+
+ 
+
+#include "Terminal.h"
+
+#include "Msg.h"
+
+#include <stdlib.h>
+
+ 
+
+/*
+
+Terminal_SendMessage is not visible to outside the Terminal.c file.
+
+This is equivalent to a private method in C++.
+
+*/
+
+ 
+
+static void Terminal_SendMessage(Terminal *pTerm, Msg *pMsg)
+
+{
+
+    /*...*/
+
+}
+
+ 
+
+void Terminal_Construct(Terminal *pTerm)
+
+{  
+
+    pTerm->terminalId = UNKNOWN;
+
+    pTerm->terminalType = UNKNOWN;
+
+    pTerm->terminalStatus = UNKNOWN;
+
+}
+
+ 
+
+void Terminal_Destroy(Terminal *pTerm)
+
+{
+
+    /*...*/
+
+}
+
+ 
+
+int Terminal_HandleRunDiagnostics(Terminal *pTerm, const RunDiagnosticsMsg *pMsg)
+
+{
+
+    int status = 1;
+
+    /*...*/
+
+   return status;
+
+}
+
+ 
+
+int Terminal_HandleOutOfService(Terminal *pTerm)
+
+{
+
+    int status = 1;
+
+    pTerm->terminalStatus = OUT_OF_SERVICE;
+
+    /*...*/
+
+    return status;
+
+}
+
+ 
+
+int Terminal_HandleInService(Terminal *pTerm)
+
+{
+
+   int status = 1;
+
+   pTerm->terminalStatus = INSERVICE;
+
+   /*...*/
+
+   return status;
+
+}
+
+ 
+
+void Terminal_Activate(Terminal *pTerm, const TerminalCreateMsg *pMsg)
+
+{
+
+    TerminalCreateAck *pAck;
+
+    pTerm->terminalId = pMsg->header.terminalId;
+
+    pTerm->terminalType = pMsg->header.terminalType;
+
+    pTerm->terminalStatus = pMsg->header.terminalStatus;
+
+    /*...*/
+
+ 
+
+    pAck = (TerminalCreateAck *)malloc(sizeof(TerminalCreateAck));
+
+    pAck->header.terminalId = pTerm->terminalId;
+
+    pAck->header.terminalStatus = pTerm->terminalStatus;
+
+ 
+
+    Terminal_SendMessage(pTerm, (Msg *)pAck);
+
+}
+
+ 
+
+void Terminal_Deactivate(Terminal *pTerm, const TerminalDeleteMsg *pMsg)
+
+{
+
+    /*...*/
+
+    pTerm->terminalId = UNKNOWN;
+
+    pTerm->terminalType = UNKNOWN;
+
+    pTerm->terminalStatus = UNKNOWN;
+
+    /*...*/
+
+}

+// Terminal class source file.
+
+ 
+
+#include "Terminal.hpp"
+
+#include "Msg.hpp"
+
+void Terminal::SendMessage(Msg *pMsg)
+
+{
+
+   //...
+
+}
+
+ 
+
+Terminal::Terminal()
+
+{  
+
+    terminalId = UNKNOWN;
+
+    terminalType = UNKNOWN;
+
+    terminalStatus = UNKNOWN;
+
+}
+
+ 
+
+Terminal::~Terminal()
+
+{
+
+    //...
+
+}
+
+ 
+
+int Terminal::HandleRunDiagnostics(const RunDiagnosticsMsg *pMsg)
+
+{
+
+    int status = 1;
+
+    //...
+
+   return status;
+
+}
+
+ 
+
+int Terminal::HandleOutOfService()
+
+{
+
+    int status = 1;
+
+    terminalStatus = OUT_OF_SERVICE;
+
+    //...
+
+    return status;
+
+}
+
+ 
+
+int Terminal::HandleInService()
+
+{
+
+   int status = 1;
+
+   terminalStatus = INSERVICE;
+
+   //...
+
+   return status;
+
+}
+
+ 
+
+void Terminal::Activate(const TerminalCreateMsg *pMsg)
+
+{
+
+    terminalId = pMsg->GetTerminalId();
+
+    terminalType = pMsg->GetTerminalType();
+
+    terminalStatus = pMsg->GetTerminalStatus();
+
+    //...
+
+ 
+
+    TerminalCreateAck *pAck = new TerminalCreateAck(terminalId, terminalStatus);
+
+    SendMessage(pAck);
+
+}
+
+ 
+
+void Terminal::Deactivate(const TerminalDeleteMsg *pMsg)
+
+{
+
+    //...
+
+    terminalId = UNKNOWN;
+
+    terminalType = UNKNOWN;
+
+    terminalStatus = UNKNOWN;
+
+    //...
+
+}

+/* Terminal struct header file. */
+
+ 
+
+#include "Msg.h"
+
+ 
+
+#define UNKNOWN 0
+
+#define OUT_OF_SERVICE 1
+
+#define INSERVICE 2
+
+ 
+
+/* Terminal struct */
+
+typedef struct
+
+{
+
+    /*...*/
+
+    int terminalId;
+
+    int terminalType;
+
+    int terminalStatus;
+
+} Terminal;
+
+ 
+
+/*
+
+Prototypes for Terminal structure related functions. Helper
+
+functions needed by these functions are marked static are not
+
+included here.
+
+*/
+
+ 
+
+void Terminal_Activate(Terminal *pTerm, const TerminalCreateMsg *pMsg);
+
+void Terminal_Deactivate(Terminal *pTerm, const TerminalDeleteMsg *pMsg);
+
+int Terminal_HandleRunDiagnostics(Terminal *pTerm, const RunDiagnosticsMsg *pMsg);
+
+int Terminal_HandleOutOfService(Terminal *pTerm);
+
+int Terminal_HandleInService(Terminal *pTerm);
+
+void Terminal_Construct(Terminal *pTerm);
+
+void Terminal_Destroy(Terminal *pTerm);

+// Terminal class header file.
+
+ 
+
+// Forward declaration for messages
+
+class TerminalCreateMsg;
+
+class TerminalDeleteMsg;
+
+class RunDiagnosticsMsg;
+
+class Msg;
+
+ 
+
+// Terminal class
+
+class Terminal
+
+{
+
+    enum { UNKNOWN = 0 };
+
+    enum {OUT_OF_SERVICE=1, INSERVICE=2};
+
+    //...
+
+    int terminalId;
+
+    int terminalType;
+
+    int terminalStatus;
+
+    void SendMessage(Msg *pMsg);
+
+ 
+
+public:
+
+    void Activate(const TerminalCreateMsg *pMsg);
+
+    void Deactivate(const TerminalDeleteMsg *pMsg);
+
+    int HandleRunDiagnostics(const RunDiagnosticsMsg *pMsg);
+
+    int HandleOutOfService();
+
+    int HandleInService();
+
+    Terminal();
+
+    ~Terminal();
+
+};

+/*
+
+TerminalManager source file. We will be using this class
+
+as an example for Object Oriented Programming in C.
+
+*/
+
+ 
+
+#include <stdio.h>
+
+#include "TerminalManager.h"
+
+#include "Msg.h"
+
+#include <stdlib.h>
+
+ 
+
+Terminal *TerminalManager_FindTerminal(TerminalManager *pMgr, int terminalId)
+
+{
+
+   if (terminalId < MAX_TERMINALS)
+
+   {
+
+       return (&(pMgr->terminals[terminalId]));
+
+   }
+
+   else
+
+   {
+
+       return NULL;
+
+   }
+
+}
+
+ 
+
+void TerminalManager_Construct(TerminalManager *pMgr)
+
+{
+
+   int i;
+
+   /*
+
+   C will not call construction functions, so loop through all call the
+
+   construction functions for all terminals.
+
+   */
+
+   for (i=0; i < MAX_TERMINALS; i++)
+
+   {
+
+      Terminal_Construct(&(pMgr->terminals[i]));
+
+   }
+
+}
+
+ 
+
+void TerminalManager_Destroy(TerminalManager *pMgr)
+
+{
+
+   int i;
+
+   /*
+
+   C will not call destruction functions, so loop through all call the
+
+   destruction functions for all terminals.
+
+   */
+
+  for (i=0; i < MAX_TERMINALS; i++)
+
+   {
+
+      Terminal_Destroy(&(pMgr->terminals[i]));
+
+   }
+
+}
+
+ 
+
+void TerminalManager_HandleMessage(TerminalManager *pMgr, Msg* pMsg)
+
+{
+
+    int status, status1;
+
+ 
+
+    int terminalId = pMsg->terminalId;
+
+ 
+
+    Terminal *pTerm = TerminalManager_FindTerminal(pMgr, terminalId);
+
+    Terminal *pOtherTerm = NULL;
+
+ 
+
+    /*
+
+    Switch on the message type and invoke the Terminal's message handlers for
+
+    the terminal specified in the message. Here the terminal manager takes
+
+    care of indexing into the terminal structure and it passes the pointer
+
+    to the terminal handler functions. Due to this design, implementation
+
+    of the terminal handler functions just focus on handling the specified
+
+    terminal.
+
+    */
+
+    if (pTerm != NULL)
+
+    {
+
+        switch (pMsg->msgType)
+
+        {
+
+        case CREATE_TERMINAL:
+
+            Terminal_Activate(pTerm, (const TerminalCreateMsg *)pMsg);
+
+            break;
+
+        case DELETE_TERMINAL:
+
+            Terminal_Deactivate(pTerm, (const TerminalDeleteMsg *) pMsg);
+
+            break;
+
+        case RUN_DIAGNOSTICS:
+
+            status = Terminal_HandleRunDiagnostics(pTerm, (const RunDiagnosticsMsg *) pMsg);
+
+            break;
+
+        case PERFORM_SWITCHOVER:
+
+            pOtherTerm = TerminalManager_FindTerminal(pMgr, pMsg->otherTerminalId);
+
+            status = Terminal_HandleOutOfService(pTerm);
+
+            status1 = Terminal_HandleInService(pOtherTerm);
+
+            break;
+
+        }
+
+    }
+
+    free(pMsg);
+
+}

+// TerminalManager source file. We will be using this class
+
+// as an example for Object Oriented Programming in C.
+
+ 
+
+#include <stdio.h>
+
+#include "TerminalManager.hpp"
+
+#include "Msg.hpp"
+
+ 
+
+TerminalManager::TerminalManager()
+
+ 
+
+{
+
+   //...
+
+}
+
+ 
+
+TerminalManager::~TerminalManager()
+
+{
+
+}
+
+ 
+
+void TerminalManager::HandleMessage(Msg* pMsg)
+
+{
+
+    int status, status1;
+
+ 
+
+    int terminalId = pMsg->GetTerminalId();
+
+ 
+
+    Terminal *pTerm = FindTerminal(terminalId);
+
+    Terminal *pOtherTerm = NULL;
+
+ 
+
+    if (pTerm != NULL)
+
+    {
+
+        switch (pMsg->GetType())
+
+        {
+
+        case CREATE_TERMINAL:
+
+            pTerm->Activate((const TerminalCreateMsg *)pMsg);
+
+            break;
+
+        case DELETE_TERMINAL:
+
+            pTerm->Deactivate((const TerminalDeleteMsg *) pMsg);
+
+            break;
+
+        case RUN_DIAGNOSTICS:
+
+            status = pTerm->HandleRunDiagnostics((const RunDiagnosticsMsg *) pMsg);
+
+            break;
+
+        case PERFORM_SWITCHOVER:
+
+            pOtherTerm = FindTerminal(pMsg->GetOtherTerminalId());
+
+            status = pTerm->HandleOutOfService();
+
+            status1 = pOtherTerm->HandleInService();
+
+            break;
+
+        }
+
+    }
+
+    delete pMsg;
+
+}
+
+ 
+
+Terminal *TerminalManager::FindTerminal(int terminalId)
+
+{
+
+   if (terminalId < MAX_TERMINALS)
+
+   {
+
+       return (&terminals[terminalId]);
+
+   }
+
+   else
+
+   {
+
+       return NULL;
+
+   }
+
+}

+/*
+
+TerminalManager header file. We will be using this class
+
+as an example for Object Oriented Programming in C.
+
+*/
+
+ 
+
+#include "Terminal.h"
+
+ 
+
+#define MAX_TERMINALS 500
+
+ 
+
+/* Structure contains all data used by the Terminal Manager. */
+
+typedef struct
+
+{
+
+    Terminal terminals[MAX_TERMINALS];
+
+} TerminalManager;
+
+ 
+
+/*
+
+ANSI C Function prototypes of all functions that operate
+
+on the TerminalManager structure.
+
+*/
+
+void TerminalManager_Construct(TerminalManager *pMgr);
+
+void TerminalManager_Destroy(TerminalManager *pMgr);
+
+void TerminalManager_HandleMessage(TerminalManager *pMgr, Msg* pMsg);

+// TerminalManager header file. We will be using this class
+
+// as an example for Object Oriented Programming in C.
+
+#include "Terminal.hpp"
+
+ 
+
+class TerminalManager
+
+{
+
+private:
+
+    enum {MAX_TERMINALS=500};
+
+ 
+
+    Terminal terminals[MAX_TERMINALS];
+
+ 
+
+    Terminal *FindTerminal(int terminalId);
+
+ 
+
+public:
+
+    TerminalManager();
+
+    ~TerminalManager();
+
+    void HandleMessage(Msg* pMsg);
+
+};

+www.w3.org/Protocols/rfc2616/rfc2616.html
\ No newline at end of file

+<HTML>
+<HEAD>
+  <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=windows-1252">
+  <META NAME="Generator" CONTENT="Microsoft Word 97">
+  <META NAME="Template" CONTENT="C:\Program Files\Microsoft Office\Office\Dictdoc.dot">
+  <TITLE>Realising the Full Potential of the Web</TITLE>
+</HEAD>
+<BODY BGCOLOR="white" TEXT="black">
+<P>
+<FONT FACE="Garamond"></FONT>
+<P>
+<H1 ALIGN="CENTER">
+  Realising the Full Potential of the Web
+</H1>
+<P ALIGN="CENTER">
+<P ALIGN="CENTER">
+Tim Berners-Lee, Director of the World-Wide Web Consortium
+<P ALIGN=CENTER>
+Based on a talk presented at the W3C meeting, London, 1997/12/3
+<P>
+&nbsp;
+<H3>
+  Abstract
+</H3>
+<P>
+<FONT FACE="Garamond"></FONT>
+<P>
+The first phase of the Web is human communication though shared knowledge.
+We have a lot of work to do before we have an intuitive space in which we
+can put down our thoughts and build our understanding of what we want to
+do and how and why we will do it. The second side to the Web, yet to emerge,
+is that of machine-understandable information. As this happens, the day-to-day
+mechanisms of trade and bureaucracy will be handled by agents, leaving humans
+to provide the inspiration and the intuition. This will come about though
+the implementation of a series of projects addressing data formats and languages
+for the Web, and digital signatures.
+<P>
+&nbsp;
+<H3>
+  The original dream
+</H3>
+<P>
+<P>
+The Web was designed to be a universal space of information, so when you
+make a bookmark or a hypertext link, you should be able to make that link
+to absolutely any piece of information that can be accessed using networks.
+The universality is essential to the Web: it looses its power if there are
+certain types of things to which you can&#146;t link.
+<P>
+There are a lot of sides to that universality. You should be able to make
+links to a hastily jotted crazy idea and to link to a beautifully produced
+work of art. You should be able to link to a very personal page and to something
+available to the whole planet. There will be information on the Web which
+has a clearly defined meaning and can be analysed and traced by computer
+programs; there will be information, such as poetry and art, which requires
+the full human intellect for an understanding which will always be subjective.
+<P>
+And what was the purpose of all this? The first goal was to work together
+better. While the use of the Web across all scales is essential to the concept,
+the original driving force was collaboration at home and at work. The idea
+was, that by building together a hypertext Web, a group of whatever size
+would force itself to use a common vocabulary, to overcome its misunderstandings,
+and at any time to have a running model - in the Web - of their plans and
+reasons.
+<P>
+For me, the forerunner to the Web was a program called &#145;Enquire&#146;,
+which I made for my own purposes. I wrote it in 1980, when I was working
+at the European Particle Physics Lab (CERN), to keep track of the complex
+web of relationships between people, programs, machines and ideas. In 1989,
+when I proposed the Web, it was as an extension of that personal tool to
+a common information space.
+<P>
+When we make decisions in meetings, how often are the reasons for those decisions
+(which we so carefully elaborated in the meeting) then just typed up, filed
+as minutes and essentially lost? How often do we pay for this, in time spent
+passing on half-understandings verbally, duplicating effort through ignorance
+and reversing good decisions from misunderstanding? How much lack of co-operation
+can be traced to an inability to understand where another party is &#145;coming
+from&#146;? The Web was designed as an instrument to prevent misunderstandings.
+<P>
+For this to work, it had to be not only easy to &#145;browse&#146;, but also
+easy to express oneself. In a world of people and information, the people
+and information should be in some kind of equilibrium. Anything in the Web
+can be quickly learned by a person and any knowledge you see as being missing
+from the Web can be quickly added. The Web should be a medium for the
+communication between people: communication through shared knowledge. For
+this to work, the computers, networks, operating systems and commands have
+to become invisible, and leave us with an intuitive interface as directly
+as possible to the information.
+<H3>
+  Re-enter machines
+</H3>
+<P>
+<FONT FACE="Garamond"></FONT>
+<P>
+There was a second goal for the Web, which is dependent on the first. The
+second part of the dream was that, if you can imagine a project (company,
+whatever) which uses the Web in its work, then there will be an map, in
+cyberspace, of all the dependencies and relationships which define how the
+project is going. This raises the exciting possibility of letting programs
+run over this material, and help us analyze and manage what we are doing.
+The computer renters the scene visibly as a software agent, doing anything
+it can to help us deal with the bulk of data, to take over the tedium of
+anything that can be reduced to a rational process, and to manage the scale
+of our human systems.
+<H3>
+  Where are we now?<FONT SIZE=2> </FONT>
+</H3>
+<P>
+The Web you see as a glorified television channel today is just one part
+of the plan. Although the Web was driven initially by the group work need,
+it is not surprising that the most rapid growth was in public information.
+Web publishing, when a few write and many read, profited most from the snowball
+effect of exponentially rising numbers of readers and writers. Now, with
+the invention of the term &#145;intranet&#146;, Web use is coming back into
+organisations. (In fact, it never left. There have always been since 1991,
+many internal servers, but as they were generally invisible from outside
+the companies&#146; firewalls they didn't get much press!). However, the
+intuitive editing interfaces which make authoring a natural part of daily
+life are still maturing. I thought that in 12 months we would have generally
+available intuitive hypertext editors. (<I>I have stuck to that and am still
+saying the same thing today!)</I>
+<P>
+It is not just the lack of simple editors that has prevented use of the Web
+as a collaborative medium. For a group of people to use the Web in practice,
+they need reliable access control, so that they know their ideas will only
+be seen by those they trust. They also need access control and archival tools
+that, like browsing, don't require one to get into the details of computer
+operating systems.
+<P>
+There is also a limit to what we can do by ourselves with information, without
+the help of machines. A familiar complaint of the newcomer to the Web, who
+has not learned to follow links only from reliable sources, is the about
+the mass of junk out there. Search engines flounder in the mass of
+undifferentiated documents that range vastly in terms of quality, timeliness
+and relevance. We need information about information, &#145;metadata&#146;,
+to help us organise it.
+<P>
+As it turns out, many of these long-term needs will hopefully be met by
+technology, which for one reason or another is being developed by the technical
+community, and agreed upon by groups such as the World-Wide Web Consortium
+(W3C), in response to various medium-term demands.
+<P>
+&nbsp;
+<P>
+<B><I><FONT FACE="Arial"></FONT></I></B>
+<H3>
+  The World Wide Web Consortium - W3C
+</H3>
+<P>
+<FONT FACE="Garamond"></FONT>
+<P>
+The Consortium exists as a place for those companies for whom the Web is
+essential to meet and agree on the common underpinnings that will allow everyone
+to go forward. (There are currently over 230 member organisations.)
+<P>
+Whether developing software, hardware, networks, information for sale, or
+using the Web as a crucial part of their business life, these companies are
+driven by current emerging areas such as Web publishing, intranet use, electronic
+commerce, and Web-based education and training. From these fields medium-term
+needs arise and, where appropriate, the Consortium starts an Activity to
+help reach a consensus on computer protocols for that area. Protocols are
+the rules that allow computers to talk together about a given topic. When
+the industry agrees on protocols, then a new application can spread across
+the world, and new programs can all work together as they all speak the same
+language. This is key to the development of the Web.
+<P>
+&nbsp;
+<P>
+<B><I><FONT FACE="Arial"></FONT></I></B>
+<H2>
+  Where is the Web Going Next?
+</H2>
+<H3>
+  Avoiding the World Wide Wait
+</H3>
+<P>
+<FONT FACE="Garamond"></FONT>
+<P>
+You've heard about it, you may have experienced it, but can anything be done
+about it?
+<P>
+One reason for the slow response you may get from a dial-up Internet account
+simply follows from the &#145;all you can eat&#146; pricing policy. The only
+thing which keeps the number of Internet users down is unacceptable response,
+so if we were to suddenly make it faster, there would almost immediately
+be more users until it was slow again. I've seen it: when we speeded up an
+overloaded server by a factor of five, it once again rose to 100% utilisation
+as the number of users increased by a factor of five.
+<P>
+Eventually, there will be different ways of paying for different levels of
+quality. But today there some things we can do to make better use of the
+bandwidth we have, such as using compression and enabling many overlapping
+asynchronous requests. There is also the ability to guess ahead and push
+out what a user may want next, so that the user does not have to request
+and then wait. Taken to one extreme, this becomes subscription-based
+distribution, which works more like email or newsgroups.
+<P>
+One crazy thing is that the user has to decide whether to use mailing lists,
+newsgroups, or the Web to publish something. The best choice depends on the
+demand and the readership pattern. A mistake can be costly. Today, it is
+not always easy for a person to anticipate the demand for a page. For example,
+the pictures of the Schoemaker-Levy comet hitting Jupiter taken on a mountain
+top and just put on the nearest Mac server or the decision Judge Zobel put
+onto the Web - both these generated so much demand that their servers were
+swamped, and in fact, these items would have been better delivered as messages
+via newsgroups. It would be better if the &#145;system&#146;, the collaborating
+servers and clients together, could adapt to differing demands, and use
+pre-emptive or reactive retrieval as necessary.
+<P>
+&nbsp;
+<P>
+<B><I><FONT FACE="Arial"></FONT></I></B>
+<H3>
+  Data about Data - Metadata
+</H3>
+<P>
+<FONT FACE="Garamond"></FONT>
+<P>
+It is clear that there should be a common format for expressing information
+about information (called metadata), for a dozen or so fields that needed
+it, including privacy information, endorsement labels, library catalogues,
+tools for structuring and organising Web data, distribution terms and annotation.
+The Consortium's Resource Description Framework (RDF) is designed to allow
+data from all these fields to be written in the same form, and therefore
+carried together and mixed.
+<P>
+That by itself will be quite exciting. Proxy caches, which make the Web more
+efficient, will be able to check that they are really acting in accordance
+with the publisher's wishes when it comes to redistributing material. A browser
+will be able to get an assurance, before imparting personal information in
+a Web form, on how that information will be used. People will be able, if
+the technology is matched by suitable tools, to endorse Web pages that they
+perceive to be of value. Search engines will be able to take such endorsements
+into account and give results that are perceived to be of much higher quality.
+So a common format for information about information will make the Web a
+whole lot better.
+<P>
+&nbsp;
+<P>
+<B><I><FONT FACE="Arial"></FONT></I></B>
+<H3>
+  The Web of trust
+</H3>
+<P>
+<FONT FACE="Garamond"></FONT>
+<P>
+In cases in which a high level of trust is needed for metadata, digitally
+signed metadata will allow the Web to include a &#145;Web of trust&#146;.
+The Web of trust will be a set of documents on the Web that are digitally
+signed with certain keys, and contain statements about those keys and about
+other documents. Like the Web itself, the Web of trust does not need to have
+a specific structure like a tree or a matrix. Statements of trust can be
+added exactly so as to reflect actual trust. People learn to trust through
+experience and though recommendation. We change our minds about who we trust
+for different purposes. The Web of trust must allow us to express this.
+<P>
+Hypertext was suitable for a global information system because it has this
+same flexibility: the power to represent any structure of the real world
+or a created imagined one. Systems that force you to express information
+in trees or matrices are fine so long as they are used for describing trees
+or matrices. The moment you try to use one to hold information that does
+not fit the mold, you end up twisting the information to fit, and so
+misrepresenting the situation. Similarly, the W3C's role in creating the
+Web of trust will be to help the community have common language for expressing
+trust. <I>The Consortium will not seek a central or controlling role in the
+content of the Web.</I>
+<P>
+&nbsp;
+<P>
+<B><I><FONT FACE="Arial"></FONT></I></B>
+<H3>
+  &#145;Oh, yeah?&#146;
+</H3>
+<P>
+<FONT FACE="Garamond"></FONT>
+<P>
+So, signed metadata is the next step. When we have this, we will be able
+to ask the computer not just for information, but why we should believe it.
+Imagine an &#145;Oh, yeah?&#146; button on your browser. There you are looking
+at a fantastic deal that can be yours just for the entry of a credit card
+number and the click of a button. "Oh, yeah?", you think. You press the
+&#145;Oh, yeah?&#146; button. You are asking your browser why you should
+believe it. It, in turn, can challenge the server to provide some credentials:
+perhaps, a signature for the document or a list of documents that expresses
+what that key is good for. Those documents will be signed. Your browser rummages
+through with the server, looking for a way to convince you that the page
+is trustworthy for a purchase. Maybe it will come up with an endorsement
+from a magazine, which in turn has been endorsed by a friend. Maybe it will
+come up with an endorsement by the seller's bank, which has in turn an
+endorsement from your bank. Maybe it won't find any reason for you to actually
+believe what you are reading at all.
+<P>
+&nbsp;
+<P>
+<B><I><FONT FACE="Arial"></FONT></I></B>
+<H3>
+  Data about things
+</H3>
+<P>
+<FONT FACE="Garamond"></FONT>
+<P>
+All the information mentioned above is information about information. Perhaps
+the most important aspect of it is that it is machine-understandable data,
+and it may introduce a new phase of the Web in which much more data in general
+can be handled by computer programs in a meaningful way. All these ideas
+are just as relevant to information about the real world: about cars and
+people and stocks and shares and flights and food and rivers.
+<P>
+The Enquire program assumed that every page was about something. When you
+created a new page it made you say what sort of thing it was: a person, a
+piece of machinery, a group, a program, a concept, etc. Not only that, when
+you created a link between two nodes, it would prompt you to fill in the
+relationship between the two things or people. For example, the relationships
+were defined as &#145;A is part of B&#146; or &#145;A made B&#146;. The idea
+was that if Enquire were to be used heavily, it could then automatically
+trace the dependencies within an organisation.
+<P>
+Unfortunately this was lost as the Web grew. Although it had relationship
+types in the original specifications, this has not generally become a Web
+of assertions about things or people. Can we still build a Web of well-defined
+information?
+<P>
+My initial attempts to suggest this fell on stony ground, and not surprisingly.
+HTML is a language for communicating a document for human consumption. SGML
+(and now XML) gives structure, but not semantics. Neither the application,
+nor the language, called for it.
+<P>
+With metadata we have a need for a machine-understandable language that has
+all the qualities we need. Technically, the same apparatus we are constructing
+in the Resource Description Framework for describing the properties of documents
+can be used equally well for describing anything else.
+<P>
+&nbsp;
+<P>
+<B><I><FONT FACE="Arial"></FONT></I></B>
+<H3>
+  A crying need for RDF
+</H3>
+<P>
+<FONT FACE="Garamond"></FONT>
+<P>
+Is there a real need for this metadata and is there a market in the medium
+term that will lead companies to develop in this direction? Well, in the
+medium term, we see the drivers already - web publishing, education and training,
+electronic commerce and intranets.
+<P>
+I have mentioned the vicious circle that caused the Web to take off initially.
+The increasing amount of information on the Web was an incentive for people
+to get browsers, and the increasing number of browsers created more incentive
+for people to put up more Web sites. It had to start somewhere and it was
+bootstrapped by making &#145;virtual hypertext&#146; servers. These servers
+typically had access to large databases - such as phone books, library catalogues
+and existing documentation management systems. They had simple programs which
+would generate Web pages &#145;on the fly&#146; corresponding to various
+views and queries on the database. This has been a very powerful
+&#145;bootstrap&#146; as there is now a healthy market for tools to allow
+one to map one's data from its existing database form on to the Web.
+<P>
+Now here is the curious thing. There is so much data available on Web pages,
+that there is a market for tools that &#145;reverse engineer&#146; that process.
+These are tools that read pages, and with a bit of human advice, recreate
+the database object. Even though it takes human effort to analyse the way
+different Web sites are offering their data, it is worth it. It is so powerful
+to have a common, well defined interface to all the data so that you can
+program on top of it. So the need for well defined interface to Web data
+in the short term is undeniable.
+<P>
+What we propose is that, when a program goes out to a server looking for
+data, say a database record, that the same data should be available in RDF,
+in such a way that the rows and columns are all labelled in a well-defined
+way. That it may be possible to look up the equivalence between field names
+at one Web site and at another, and so merge information intelligently from
+many sources. This is a clear need for metadata, just from looking at the
+trouble libraries have had with the numbers of very similar, but slightly
+different ways of making up a catalogue card for a book.
+<P>
+&nbsp;
+<P>
+<B><I><FONT FACE="Arial"></FONT></I></B>
+<H3>
+  Interactive Creativity
+</H3>
+<P>
+<FONT SIZE=2></FONT>
+<P>
+&nbsp;
+<P>
+<FONT FACE="Garamond"></FONT>
+<P>
+I want the Web to be much more creative than it is at the moment. I have
+even had to coin a new word - Intercreativity - which means building things
+together on the Web. I found that people thought that the Web already was
+&#145;interactive&#146;, because you get to click with a mouse and fill in
+forms! I have mentioned that better intuitive interfaces will be needed,
+but I don&#146;t think they will be sufficient without better security.
+<P>
+It would be wrong to assume that digital signature will be mainly important
+for electronic commerce, as if security were only important where money is
+concerned. One of my key themes is the importance of the Web being used on
+all levels from the personal, through groups of all sizes, to the global
+population.
+<P>
+When you are working in a group, you do things you would not do outside the
+group, You share half-baked ideas, reveal sensitive information. You use
+a vernacular that will be understood; you can cut corners in language and
+formality. You do these things because you trust the people in the group,
+and that others won't suddenly have access to it. To date, on the Web, it
+has been difficult to manage such groups or to allow one to control access
+to information in an intuitive way.
+<P>
+&nbsp;
+<P>
+<B><I><FONT FACE="Arial"></FONT></I></B>
+<H3>
+  Letting go
+</H3>
+<P>
+<FONT FACE="Garamond"></FONT>
+<P>
+So, where will this get us? The Web fills with documents, each of which has
+pointers to help a computer understand it and relate it to terms it knows.
+Software agents acting on our behalf can reason about this data. They can
+ask for and validate proofs of the credibility of the data. They can negotiate
+as to who will have what access to what and ensure that our personal wishes
+for privacy level be met.
+<P>
+The world is a world of human beings, as it was before, but the power of
+our actions is again increased. The Web already increases the power of our
+writings, making them accessible to huge numbers of people and allowing us
+to draw on any part of the global information base by a simple hypertext
+link. Now we image the world of people with active machines forming part
+of the infrastructure. We only have to express a request for bids, or make
+a bid, and machines will turn a small profit matching the two. Search engines,
+from looking for pages containing interesting words, will start indexes of
+assertions that might be useful for answering questions or finding
+justifications.
+<P>
+I think this will take a long time. I say this deliberately, because in the
+past I have underestimated how long something will take to become available
+(e.g. good editors in 12 months).
+<P>
+Now we will have to find how best to integrate our warm fuzzy right-brain
+selves into this clearly defined left-brain world. It is easy to know who
+we trust, but it might be difficult to explain that to a computer. After
+seeding the semantic Web with specific applications, we must be sure to
+generalise it cleanly, leaving it clean and simple so that the next generation
+can learn its logical concepts along with the alphabet.
+<P>
+If we can make something decentralised, out of control, and of great simplicity,
+we must be prepared to be astonished at whatever might grow out of that new
+medium.
+<H3>
+  It&#146;s up to us
+</H3>
+<P>
+<FONT SIZE=2> </FONT>&nbsp;
+<P>
+One thing is certain. The Web will have a profound effect on the markets
+and the cultures around the world: intelligent agents will either stabilise
+or destabilise markets; the demise of distance will either homogenise or
+polarise cultures; the ability to access the Web will be either a great divider
+or a great equaliser; the path will either lead to jealousy and hatred or
+peace and understanding.
+<P>
+The technology we are creating may influence some of these choices, but mostly
+it will leave them to us. It may expose the questions in a starker form than
+before and force us to state clearly where we stand.
+<P>
+We are forming cells within a global brain and we are excited that we might
+start to think collectively. What becomes of us still hangs crucially on
+how we think individually.
+<P>
+  <HR>
+<P>
+</BODY></HTML>

+<rdf:RDF
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
+   xmlns:owl="http://www.w3.org/2002/07/owl#" 
+   xmlns:dc="http://purl.org/dc/elements/1.1/">
+
+ <owl:Ontology 
+     rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
+   <dc:title>The RDF Vocabulary (RDF)</dc:title>
+   <dc:description>This is the RDF Schema for the RDF vocabulary defined in the RDF namespace.</dc:description>
+ </owl:Ontology>
+ 
+ <!-- Added by Ivan Herman, 2010-12-30, from here... -->
+ <rdfs:Datatype rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#PlainLiteral">
+   <rdfs:subClassOf rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/>
+   <rdfs:isDefinedBy rdf:resource="http://www.w3.org/TR/rdf-plain-literal/"/>
+   <rdfs:label>PlainLiteral</rdfs:label>
+   <rdfs:comment>The class of plain (i.e. untyped) literal values.</rdfs:comment>
+</rdfs:Datatype>
+<!-- ... until here -->
+ 
+
+<rdf:Property rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#type">
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>type</rdfs:label>
+  <rdfs:comment>The subject is an instance of a class.</rdfs:comment>
+  <rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class"/>
+  <rdfs:domain rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>
+</rdf:Property>
+
+<rdfs:Class rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#Property">
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>Property</rdfs:label>
+  <rdfs:comment>The class of RDF properties.</rdfs:comment>
+  <rdfs:subClassOf rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>
+</rdfs:Class>
+
+<rdfs:Class rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#Statement">
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>Statement</rdfs:label>
+  <rdfs:subClassOf rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>
+  <rdfs:comment>The class of RDF statements.</rdfs:comment>
+</rdfs:Class>
+
+<rdf:Property rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#subject">
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>subject</rdfs:label>
+  <rdfs:comment>The subject of the subject RDF statement.</rdfs:comment>
+  <rdfs:domain rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Statement"/>
+  <rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>
+</rdf:Property>
+
+<rdf:Property rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate">
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>predicate</rdfs:label>
+  <rdfs:comment>The predicate of the subject RDF statement.</rdfs:comment>
+  <rdfs:domain rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Statement"/>
+  <rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>
+</rdf:Property>
+
+<rdf:Property rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#object">
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>object</rdfs:label>
+  <rdfs:comment>The object of the subject RDF statement.</rdfs:comment>
+  <rdfs:domain rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Statement"/>
+  <rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>
+</rdf:Property>
+
+<rdfs:Class rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#Bag">
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>Bag</rdfs:label>
+  <rdfs:comment>The class of unordered containers.</rdfs:comment>
+  <rdfs:subClassOf rdf:resource="http://www.w3.org/2000/01/rdf-schema#Container"/>
+</rdfs:Class>
+
+<rdfs:Class rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#Seq">
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>Seq</rdfs:label>
+  <rdfs:comment>The class of ordered containers.</rdfs:comment>
+  <rdfs:subClassOf rdf:resource="http://www.w3.org/2000/01/rdf-schema#Container"/>
+</rdfs:Class>
+
+<rdfs:Class rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#Alt">
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>Alt</rdfs:label>
+  <rdfs:comment>The class of containers of alternatives.</rdfs:comment>
+  <rdfs:subClassOf rdf:resource="http://www.w3.org/2000/01/rdf-schema#Container"/>
+</rdfs:Class>
+
+<rdf:Property rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#value">
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>value</rdfs:label>
+  <rdfs:comment>Idiomatic property used for structured values.</rdfs:comment>
+  <rdfs:domain rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>
+  <rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>
+</rdf:Property>
+
+<!-- the following are new additions, Nov 2002 -->
+
+<rdfs:Class rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#List">
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>List</rdfs:label>
+  <rdfs:comment>The class of RDF Lists.</rdfs:comment>
+  <rdfs:subClassOf rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>
+</rdfs:Class>
+
+<rdf:List rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#nil">
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>nil</rdfs:label>
+  <rdfs:comment>The empty list, with no items in it. If the rest of a list is nil then the list has no more items in it.</rdfs:comment>
+</rdf:List>
+
+<rdf:Property rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#first">
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>first</rdfs:label>
+  <rdfs:comment>The first item in the subject RDF list.</rdfs:comment>
+  <rdfs:domain rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#List"/>
+  <rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>
+</rdf:Property>
+
+<rdf:Property rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#rest">
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>rest</rdfs:label>
+  <rdfs:comment>The rest of the subject RDF list after the first item.</rdfs:comment>
+  <rdfs:domain rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#List"/>
+  <rdfs:range rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#List"/>
+</rdf:Property>
+	
+<rdfs:Datatype rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral">
+  <rdfs:subClassOf rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/> 
+  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
+  <rdfs:label>XMLLiteral</rdfs:label>
+  <rdfs:comment>The class of XML literal values.</rdfs:comment>
+</rdfs:Datatype>
+
+<rdf:Description rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
+  <rdfs:seeAlso rdf:resource="http://www.w3.org/2000/01/rdf-schema-more"/>
+</rdf:Description>
+
+</rdf:RDF>
+

+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
+   "http://www.w3.org/TR/REC-html40/loose.dtd">
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
+<title>Book outline</title>
+<link rel="stylesheet" href="/StyleSheets/public.css">
+</head>
+<body bgcolor="#f8fed3" text="black" link="blue" vlink="green" style="color:
+#000000;background-color: #FFF8ED" lang="en">
+
+<p></p>
+
+<p>Transcript of <a
+href="http://www.w3.org/People/Berners-Lee/Overview.html#Talks">Tim
+Berners-Lee</a>'s talk to the LCS 35th Anniversary celebrations, Cambridge
+Massachusetts, 1999/April/14. See also:</p>
+<ul>
+<li>
+<a href="../../Talks/1999/0414-LCS35-tbl/slide1-1.html">Slides</a>
+</li>
+<li>
+<a href="http://www.lcs.mit.edu/">MIT Laboratory for Computer Science</a>
+</li>
+<li>
+<a href="http://www.lcs.mit.edu/anniv/agenda/">MIT LCS 35th Anniversary
+</a>(April 1999)
+</li>
+</ul>
+
+<p>[edited for comprehensibility]</p>
+
+<p></p>
+
+<p>TIM BERNERS-LEE: It's a great pleasure to be addressing you on this 35th
+anniversary. Of  course, it's a 35th anniversary of LCS, and it's also the
+35th anniversary  of the Web, if you count in Web years.  [Laughter.]</p>
+
+<p>I will say a little bit about where I'm coming from, what the original idea
+was, because I don't want to talk about the future as a prediction. I don't
+give predictions. That I leave to Bob. It's dangerous: you end up eating your
+articles, and so I will stick to talking about what  I would like to see
+partly because when there are a bunch of people from LCS  in the audience, the
+next thing you find is somebody has come around to your office,  knocked on
+the door, and said that, by the way, they've done it.</p>
+
+<p>When I'm talking about what I would like to see, you know, it  hasn't
+changed very much in ten years. So if I talk about where I'm coming from, what
+I  wanted to see then, then, that's two-thirds of my hopes for the future.
+I'll give a little bit of history of how where the World Wide Web Consortium
+came to  LCS, and then I'll talk a bit about the Web and about an interesting
+distinction  between what we used to call documents, and what we used to call
+data.</p>
+
+<p>The basic ideas of the Web is that an information space through which
+people can  communicate, but communicate in a special way: communicate by
+sharing their  knowledge in a pool. The idea was not just that it should be a
+big browsing medium. The idea was that everybody would be putting their  ideas
+in, as well as taking them out. This is not supposed to be a  glorified
+television channel Also everybody should be excited about the  power to
+actually create hypertext.  Writing hypertext is good fun, and  being with a
+group of people writing hypertext and trying to work something  out, by making
+links is a different way of working. I hoped that it  would be a way that
+soon, for example, the European Particle Physics Laboratory at Geneva,
+Switzerland, where I was at the time. I'd hoped it would be a way for us to
+much more efficiently use people who came and went, use student work,  use
+people working remotely. And leave a trail, not a paper trail, but a  trail in
+hyperspace.</p>
+
+<p>So I had hoped that the Web would be a tool for us, understanding each
+other and working together efficiently on larger scales. Getting over the
+problem which befalls the organization that was so fun when it was a start-up
+of six people (many of you will know about this phenomenon).  When you get to
+60 people it is still great fun, and you're still rollerblading in the parking
+lot. And then when you get to 61 people, you worry that you don't know that
+person's name, and the difficulties of scaling the organization set in.</p>
+
+<p>There's a second half to the dream really, and I must admit that originally
+I was  a little bit careful about expressing this.  But the second half is the
+hope that when  we've got all of our organization communicating together
+through this medium which is accessible to machines, to computer programs,
+that there will be some cool computer programs which we could write to analyze
+that stuff: to figure out how the organization really runs; and what is its
+real structure, never mind the structure we have given it;  and all kinds of
+things like that. And to do that, of course, the information on the Web  would
+have to be understandable to some extent by a machine and at the moment it's
+not.</p>
+
+<p>Here is a very basic history overview.  I originally wrote a proposal.
+That's the piece of paper which I dropped  into the time capsule, for those of
+you who were at the party. I wrote the  proposal in 1989 and tried to explain
+that I thought the global hypertext  would be a great idea. Now, the world is
+full of people writing these  proposals and since Vennevor Bush started in
+1945 and it was published in  the Atlantic Monthly and still nobody developed
+a global hypertext system.  And then Doug Enbgelbart actually showed people
+how to do it two decades  later, and still it didn't happen because he just
+didn't happen to be in the  right place at the right time. But I was.</p>
+
+<p>I was in right place in that  the European particle physics community was
+full of people with machines  on their desk &mdash;  now just about starting
+to be Internet worked: connected to the Internet as opposed to all sorts of
+proprietary networks. And I was at a place where my boss Mike Sandel and his
+boss David Williams, who is sitting down here, were prepared to not say no.
+They let me go ahead and do it, "even though we can't actually justify it."
+That happened actually in 1990 when I bought one of those new NeXT machines,
+which was a great programming environment in lots of ways. I could actually
+put together a hypertext editor,  (browser/editor; it was the same
+thing&mdash;It was modeless) pretty quickly.  And then in the summer of '91 we
+actually released the  code, put it up on an FTP server and drew people's
+attention to the first  Web site and the first Web client and started to try
+to push this. It was still very difficult, you know, to explain how exciting
+global hypertext is if you only have a couple of Web pages.   That may seem
+silly now and obvious, but it's very difficult to show the excitement in  one
+Web page.</p>
+
+<p>The excitement of a hypertext link is that it can point to anything  out
+there. When there's nothing out there then that is just difficult  to
+demonstrate. So for several years it's a question of first trying to  justify
+my existence. In fact I wasn't working on anything else, and the  other people
+who had got onto the team one way or another. They sort of slipped through,
+working in different places, working  across the world collaborating over the
+Internet. And persuading people to  put out Web browsers was tricky.  It
+involved all kinds of doing sneaky things,  suggesting that they needed a Web
+browser for a very specific application  so that they would get it and then
+that they would be&mdash;they would just  increase the number of clients out
+there which would increase the incentive  for somebody to put up a server and
+vice-versa. And eventually the thing  started snowballing.</p>
+
+<p>Now, in 1992 it was clear that it was taking off. It still wasn't clear
+that it would, for example ever take over from the Internet Gopher,  which was
+another system expanding exponentially on the  Internet. But people were
+already starting to come into my office.  Alan Kotok from Digital came with
+three colleagues, unannounced. Now, people  don't generally drop in Geneva
+unannounced, particularly Americans.   We found a conference room quickly and
+he explained that they were starting to investigate what Digital should do,
+how Digital should address  this "Internet" and the World Wide Web.  "We're
+concerned about stability and  we understand that it all hinges on some
+specifications which you have  stored on a disk somewhere..".  They wondered
+how stable they were and how  we get to insure their continued stability and
+their evolution.</p>
+
+<p>I started talking with them and other people about what sort of a  body we
+needed to make sure that the Web would evolve into something we could
+use&mdash;now it  was becoming a serious thing. They were very adamant, like
+everyone  else, that there should be some neutral forum where people could
+meet.  I started shopping around. I looked at a number of  different
+possibilities:  setting it up as a company; joining a large company  and
+setting it up base there, setting it up at some other institution. I traveled
+around a bit and talked to a lot of people and there's one place which came up
+with checks in all the boxes. In fact it  was on a bus going from a conference
+dinner in Newcastle in northern England on one rainy night to a small hotel
+that I sat next to David Gifford from LCS, who listened to the story politely
+and said I  should mail this Michael D
+something&mdash;<code>mld@hq.lcs.mit.edu</code>&mdash;and he might  be
+interested.</p>
+
+<p>I did and next thing Michael dropped in in Zurich and from  then on I
+discovered that not only could I sell him the idea of setting up  as a base in
+the U.S. but I could sell him on the idea of setting it up as  an
+international thing. He was just as enthusiastic as me about  that. So that's
+the story of how the Web Consortium came to LCS. And the  rest is more or less
+history and acronyms, and I won't to into the acronyms  in case you are
+frightened about them. But basically things have been  happening.</p>
+
+<p>The fundamental thing about the space&mdash;about this Web, as I said, is
+that anything  can refer to anything. Otherwise it's no fun. You've got to be
+able to  make the link to anything. It's no good asking people to put things
+on the Web, saying that anything of importance should have this "URL",if you
+then request anything else. To  make such an audacious request you have to
+then release anything else. So  that requires that the Web has completely
+minimalist design. We don't  impose anything else. It has to be independent of
+anything.  The great challenge, really the raison d'etre initially for getting
+the Web protocols out, was to be independent of hardware platform: to be able
+to  see the stuff on the mainframe from your PC and to be able to see the
+stuff  on the PC from the Mac. To get across those boundaries was at the time
+so  huge and strange and unbelievable. And if we don't do things right it will
+be huge and strange and unbelievable again:  we could go back down that route
+very easily.</p>
+
+<p>It was important to get it should be independent of software. The World
+Wide Web originally was a client program called "World  Wide Web". I
+eventually renamed the program because I didn't want the World Wide  Web to be
+one program. It's very important that any program that can talk the World Wide
+Web protocols&mdash;(HTTP, HTML,...) can provide equivalent access to the
+information.</p>
+
+<p>It's very important to be independent of the way you actually happen to
+access this information. We're using a rather large screen here but it  works
+just as well on this small screen. It should also work if you need  to have
+these read to you, because maybe you're visually impaired or maybe  you're
+driving along. 20 percent of the people who have access to the Web have some
+sort of  impairment; maybe they can see the screen fine but they can't use a
+mouse.  So it's very important that we separate the content from the way we're
+presenting it.  This slide is just an HTML file, but it has a style sheet that
+says it needs to be big and it  should be white on blue according to the
+guidelines.</p>
+
+<p>It's important that the Web should be independent of language and culture,
+and I could now talk for two hours just about that. In the  Consortium, just
+as we have a Web accessibility initiative addressed the question of
+accessibility, we have  an activity which looks specifically about
+internationalization. But then  you have to add culture, then you're talking
+about a whole lot more than  just using Unicode and just making sure that you
+can make the letters go  up and down the page instead of across the page.</p>
+
+<p>It's important that the Web should be independent of quality of
+information. I don't want it to be somewhere where you would publish technical
+reports only after you had finished. If you can link to anything I want this
+to be part of the process. So the review of the technical report and the
+scribbling of the original note which led to the idea that became the project
+which resulted in the technical report should all be there and they should all
+be linked together. So it's very important that you should be  able to
+instantly go in there and edit.  (Now actually I'm very sorry that this is not
+my machine so  I'm not using my editor. Otherwise I would be able to just go
+into this slide and  put the cursor in the middle and edit the slide.)  At the
+same time, when I use the word "quality," it's important to remember that the
+idea of quality is  completely subjective. So the Web shouldn't have in it any
+particular built-in notion of what quality means at all.</p>
+
+<p>There are one, two, three, four,  five, six dimensions I have mentioned
+along which documents on  the Web can vary. Throughout all the history and
+through the future evolution it's been very important to maintain this
+invariance  with all the fancy new ideas that came in. Every now and again we
+get  a new suggestion that flagrantly violates one of these areas, and we have
+to find ways to turn it around and express it in a way which  does not.</p>
+
+<p>The last dimension of independence is an interesting one. There's a
+difference between  documents and data. This division that David Williams used
+to lead originally was called "Documents and Data." There was a feeling around
+the organization that it was a very funny old name, and it should be  renamed
+as "Computing and Networking," and now it's probably being renamed  as
+"Information Technology," or "Information Systems". But at one point  it was
+Documents and Data. And perhaps that was the silliest name at all,  but
+perhaps it was the most insightful.  Because on the Web you find "documents"
+of the sorts of things people read and write, and you find "data" out there
+which is the sorts of things machines read and write. And that distinction  is
+interesting. And it's important that the Web should allow everything on  that
+spectrum as well; that we should have things which are very  specifically
+aimed at people, caligraphy and poetry. At the same time we should have hard
+data which is processable very efficiently, and logic which can be analyzed by
+a machine. And things in  between.   A lot of the Web is sort of things in
+between. When you hit a Web page  which has stock prices on it, there is data
+on there. You're looking for  data. When you look for the weather you're
+looking for data but it comes in  this sort of dressed up fashion with a nice
+pink flashing border and a few  ads at the top in a way that's designed to
+appeal to you and entice you to  buy things.</p>
+
+<p>So you could think of it, if you like, as three layers:  at the top, there
+is the   presentation layer. For this slide it's defined by style sheet. And
+in  the middle there's content, a funny word which seems to be  popular on the
+Web nowadays.  This, the HTML code, which  says that this thing which in fact
+the style sheet had turned yellow is a  first level heading, and this thing is
+an unordered list.  And then underneath&mdash;there isn't a lot on this page I
+would say would be  data. There's a metadata at the top which gives the
+relationship  between this slide and the other slides. But the data are the
+things like  the stock prices and who actually wrote this and when it was
+created, and  what we think the weather is going to be like tomorrow in Boston
+and things  like that.</p>
+
+<p>I'm going to contrast these two sides a little bit. Because when we're
+looking at the way forward and also when we're assessing how far we've got,
+those are the two benchmarks.</p>
+
+<p>How well are we doing? Are we doing human communication through shared
+knowledge? Let's look through the  document side.  On this side the languages
+are natural language. They're people talking  to people. So the language is
+you just can't analyze them very well. And  this is the big problem on the net
+for a lot of people, is the problem for  my mother and your mother and our
+kids. They go out to search  engines and they ask a question and the search
+engine gives these stupid answers. It has read a large proportion of the pages
+on the entire Web (which is of course amazing)  but it doesn't understand any
+of them &mdash; and it tries to answer the question on that basis.  Obviously
+you get pretty unpredictable results.  However, the wonderful thing is that
+when people communicate in this way, this  kind of fuzzy way, people can solve
+problems intuitively. When people browse across the Web and see something
+expressed in natural language, they think, "Aha!" and suddenly solve a totally
+unrelated problem due to the incredible ability that the human brain has to
+spot a pattern totally out of context by a huge amount of parallel
+processing.</p>
+
+<p>It's very important that we use this human intuitive ability because
+everything else we can automate, but we're not very good at automatically
+doing that. I  wanted the Web to be what I call an interactive space where
+everybody can  edit. And I started saying "interactive," and then I read in
+the media that the Web was great because it was "interactive," meaning you
+could click. This was not what I meant by interactivity, so I started calling
+it  "intercreativity". (I don't generally believe in making up words to solve
+problems, so I'm sorry about this one.) What I mean is being creative with
+others. A few fundamental rules make this possible.  As you can read, so you
+should be able (given the authority) to write. If you can see  pictures on
+your screen, why can't you take pictures and very easily and  intuitively put
+them up there? You feel that you know how to use the Web?  Somebody yesterday
+asked me, "What's the problem? The Web is so intuitive.  Hasn't it solved that
+problem?" I asked,<br>
+"Do you take digital  photographs?" <br>
+"Yes"<br>
+"So how long does it take you to get them on a Web page so the rest of the
+family can see them?"<br>
+"Oh, I wouldn't know how to do that."</p>
+
+<p>We're certainly not there. At the moment I certainly cannot put the cursor
+in the middle of this slide and correct a spelling mistake. So in fact there's
+a huge amount we have to do.  One of the reasons this is difficult is that
+it's actually hard. The research community produced group editors which would
+allow you to  edit documents and share a document. And while two people are
+working at  the same time&mdash;we know how to do that; we the academic
+community.  But I don't have it here now. I can't edit this so that somebody
+watching  this on a broadcast can see the edit at the same time.</p>
+
+<p>So one of the reasons is that it's actually hard to get the software
+working seriously, as a product. It also needs a whole lot of infrastructure.
+We need a lot more stability. We need people to learn to stop changing URL's,
+so links don't break. That's just a question often of hygiene and making an
+organizational commitment, when you put something on the Web, to keeping  it
+there.  But also, underneath, we need digital signature. We need digital
+signature so that when you share things with your colleagues you know that
+you're sharing it with your colleagues and you're not sharing it with just
+anybody, any hacker who happened to turn up on that strip of Ethernet.  So if
+you ask me what is the most important thing for us to do over the  next 35
+years, that I would hope in the next five to ten years we can fix this. We can
+fix this so that you can use the Web intuitively as the way that you express
+an "aha!", a thought, the moment that you think of something. And I can fix
+this slide the moment I realize it's got garbage on the bottom.</p>
+
+<p>Now a look on the other side. The other side is very different.  Data has
+very well-defined meaning. So typically a huge number of Web pages are
+generated from databases.  The people who produce the databases may, when they
+started it with a  little spreadsheet, have had a vague idea of what the
+columns meant, but  by now have a very good idea of what the columns mean. The
+database expresses  well-defined relationship between things in the columns.
+When you had  a weather server to pick up the temperature in Massachusetts, in
+fact  the person behind it knows that this is the temperature in degrees
+Centigrade measured at seven o'clock in the morning at Logan Airport using
+this little thermometer four feet above the ground by that little bench  that
+you see on the television.  So there is well-defined data and there are
+well-defined things you do  with it. When you write a digital check a fairly
+well-defined thing has  got to happen. And when you look at your bank
+statement after having written the check and the check having even been
+cashed, there's got to be a very simple logical relationship between those
+things. You don't generally send pieces of poetry, which should give the bank
+a feel for the amount of money to pay to the payee.</p>
+
+<p>At the moment there's a very strange phenomenon going on. The data is being
+exported as Web pages. There are programs which want to process that data, who
+want to, for example, analyze the stock prices, who want to look at all the
+bookstores and find out where you can get that book cheapest and then present
+you with a comparative shopping list&mdash;and there are lots of Web sites out
+there. If you're not using one, do:  you could save yourself some money.
+What's happening is that they are often going out to a Web site which may or
+may not  be cooperative: it may just be putting that information on the Web.
+Sometimes the Web sites that they are scraping for data, would not cooperate
+if asked to. But the data is out there; it's available. And so  you have one
+program which is turning it from data into documents, and  another program
+which is taking the document and trying to figure out where  in that mass of
+glowing flashing things is the price of the book. It  picks it out from the
+third row of the second column of the third table in  the page. And then when
+something changes suddenly you get the ISBN  number instead of the price of a
+book and you have a problem.  This process is called "screen scraping," and is
+clearly ridiculous,  and the fact that everybody is doing it shows to me that
+there is a very  very clear demand for actually shipping the data as data. So
+that if  somebody wants to do an SQL query, if somebody wants to query an
+object out  here, they don't have to go through this whole simulation of a
+very simple  query in order to actually get at the data.</p>
+
+<p>The idea of "the semantic Web" is the side of the Web where data has
+meaning. What's meaning? I'm not  suggesting that you should program your
+computer to understand the meaning  of life right now. I am using meaning in
+the sense that either there is a program which knows somehow how to pay a
+check and  therefore can just process a check, or somebody has to find a
+relationship  between what the documents, the checks, call price and what this
+catalog  calls price. So there has been a link made between the meaning of one
+column and the meaning of another. So meaning in general on the semantic  Web
+is defined relatively. Just like in a dictionary.</p>
+
+<p>Don't panic. I'm  not becoming relativist about my morals. I'm just
+pointing out that all definitions that we use at the moment are relative to
+other definitions and so on just as in a dictionary. One of the things which
+we are doing now is we are moving to a state when  all documents will be self
+defining, self describing. So with the top of a  document which uses all kinds
+of tags like price and shoe size there will  be a URL of the document that
+defines exactly what shoe  size means in this context.  We won't have remove
+this ambiguity which happened when we extended HTML and  started putting cool
+things like tables into HTML. People who were around in those days will
+rememeber how the word spread that it would be really nice to  have tables in
+HTML: you couldn't put a table in a Web page before that.  But everybody
+started doing it at once and when anyone started a table they marked up in the
+HTML code with "<code>&lt;TABLE>"</code>. So when you read "&lt;TABLE>"  you
+had no  idea what sort of markup was coming in. And  that lasted until we
+organized a global meeting of all the people involved  to agree on it.</p>
+
+<p>Now, we can't&mdash;every time somebody wants to think of a new idea, a new
+term, a new column in a database&mdash;have a global meeting to decide about
+it. We have to let people invent new terms all the time as they do anyway, but
+just make sure there's no ambiguity.  Also we have to allow people to combine
+more than one vocabulary in the  document. We don't just want to make
+something which works; we want to  make something which can evolve. This is
+very important from the point of  view of the World Wide Web Consortium
+cutting itself out of the loop as  much as possible.</p>
+
+<p>We have 320 members, various types&mdash;companies, organizations,
+individuals&mdash;all coming together to discuss global status. and we can't
+do that when you want to invent languages for pharmaceuticals, languages  for
+whatever your favorite new database application may be.  What we need to be
+able to do is to be able to send documents around which  use standard
+vocabulary, and add extensions in in a well-defined way; which mix in the
+extensions, so that somebody who understands the standards but  doesn't an
+extension can figure out whether this is a problem. And in the case  that the
+data is in fact just informational data on the side, can process the rest.
+This in fact allows us to move from using one vocabulary to another
+vocabulary.</p>
+
+<p>This partial understanding sounds like a failure. But in fact partial
+understanding is what allows us to actually function in the world. If you
+think of an invoice, if you send an invoice from one company to another,  when
+it's paid, the person who allows that to be paid and sends the check  off,
+checks various fields on that invoice and checks that it's been  authorized an
+appropriate person. They check the amount, but when they  look at the parts
+they don't have to understand exactly what a "lower  left-hand engine bearing
+cover bolt  bracket"  is, because that part of the document is in fact
+completely ignorable  for purposes of paying the invoice.  A huge amount of
+information, stuff we read, everything that runs our  business, is like that.
+There are documents going around in which  different people understand
+different parts. And that is how we can extend  the language. And that is how
+we can evolve the whole of society that uses  this language. If we're going to
+be moving to the semantic Web we have  to be able to do that.</p>
+
+<p>We've talked a lot during this fest about digital signature. And, of
+course, digital signature, if we were only allowed to do it, would be
+fundamental to this. And it will be fundamental to this. We have, in  fact,
+directly following this on Thursday and Friday, at the Consortium, a workshop
+about signing XML, the basic language for data, with digital
+signatures.Digital signature on top of the semantic Web turns it into a Web of
+trust in which a computer can not only reason and make deductions, using not
+only the logic of it, but also the model of trust.  I  could also talk to you
+about this for six hours, but I won't.</p>
+
+<p>Let's look about what happens as we scale these things up. Remember the
+human side that when the Web was difficult to sell not only because looking at
+two hypertext pages wasn't sufficient to make people  very excited, but also
+there was a certain fear that the Web would break  structures. There was a lot
+of people I spoke to initially wanted the Web  to be hierarchical because they
+wanted the hierarchical feeling of control. Or they decided the  best
+documentation system for them was a matrix. In fact the Web broke out  of the
+box and allowed you to express a hierarchy or a matrix equally well, but it
+allowed you to express other things, too, which was a little bit frightening.
+It's been a dramatic change for the individual. I am, of course,  very
+interested in whether it can be a dramatic change for society. And  I've got a
+feeling that I could talk for two hours about most of these  points.</p>
+
+<p>A really exciting thing would be if we could scale that ability to make
+intuitive leaps. I've always wanted to be able to do this with a group, of
+very bright, very enthusiastic people really interested in specific
+overlapping areas, say LCS, or all the people who are trying to find a cure
+for AIDS, or whatever. A typical thing researcher tries to do is to get as
+much into his or her head  at once and then hope that the solution forms, the
+penny drops, that  connection is made, and they can write it down before they
+go to sleep.  How can you get a group of people to do the same thing? Maybe if
+we  can use the Web as a very low bandwidth ineffective small set of neural
+connections which connect the people. Imagine that one person surfing the Web
+can  leave a trail.  In other words, if somebody, as they're surfing the Web
+and they notice an interesting association and connection can represent that
+with a link, then another person surfing the  Web on another topic maybe find
+that link and use it and as a result bring  a new communal path a little bit
+further on. And so the group as a whole after a  while will be able to make
+that "Aha!". That's something I would find very  exciting.</p>
+
+<p>On the other side, promoting the machine communication is running across
+all  the same hopes and fears as promoting the human communication. The same
+problems that&mdash;when suggesting this to somebody, it's very difficult to
+explain how if you, instead of just putting a database on the Web you put  it
+on in a way that everything has a URL and it's part of a Web&mdash;that when
+all the databases are linked together, and when there are links
+meaning&mdash;when there are links between the meaning of this column and the
+meaning, well, that's not very exciting when I just described it as, you know,
+the last name in this is the same as the last name in this. But  imagine that
+all the last name columns in all the databases on the Web were  all directly
+or indirectly linked together by links. Then effectively you'd be able to join
+any databases that talk about the last name of a  person on that together.
+You'd be able to query the whole Web as all the  data on Web is one huge
+database. Which would be very very powerful, and  I'm glad we talked about
+privacy yesterday.  So the same rules have to apply. Anything can refer to
+anything. Wherever there was an identifier in your data language suddenly you
+have to  be able to use a URI, and there's a certain amount of resistance to
+that.  Because people want to maintain the fact that the systems are
+predictable.  They don't want the language to become too expressive, because
+computer  science is all about&mdash;this is perhaps a little unfair&mdash;the
+art of designing  languages which are sufficiently constraining so that you
+can only write solvable problems in them. If you look at a particular query or
+you  look at the language of writing what you can ask an ATM to do it's very
+simple, because an ATM can only do a few things.  But when you link together
+all the data you end up with a representation  of the world, and the world is
+a very complex place, and you need an  arbitrarily expressive language for
+expressing that.</p>
+
+<p>We end up with  this tension between that and systems which we will be
+producing which will be predictable, like checks. We will have to constrain
+the checks so that  you can only put an integer in there. You cannot put an
+expression, say  that this is "pay the bearer on demand the smallest number
+expresseable in two distinct ways as the sum of two cubes", or something which
+Ron will cook up you can only calculate it in 35 years. People want that check
+to terminate. They want the payment to happen in a finite time. They're very
+worried when we suggest that the underlying structure for this  will be very
+expressive.  But in fact, when you put all these systems together, the result
+will be  all the independent machines &mdash; Michael's bulldozers&mdash;
+taken together will be a huge very very complex map of the world.</p>
+
+<p>I used to say that the Web would mimic the world. In fact, it ends up being
+the world to a certain extent. So the well be on their heuristics, we will not
+have to use heuristics, don't panic, in order to pay checks. But it  will be a
+very exciting place to explore algorithms which break what we  call the closed
+world assumption of the people who try to export things in  boxes without any
+breathing holes.  Of course, the really exciting thing happens when we mix the
+two worlds.  I don't know we can solve any serious problems unless we do. I'm
+not  asking for the machines to join the human world with artificial
+intelligence. I'm happy for other people to ask for that. But I'm just  saying
+that if we as humans, when we have gone already to the trouble of putting data
+into databases, putting our schedules, our appointments into a schedule
+database&mdash;we've already in other cases done that; it's in a very
+well-defined form. Let's not lose that information. Let's not lose that
+semantics. Let's use it. Let's digitally sign it. Let's allow machines  to
+start operating on it. And with this mixture of predictable mechanisms  of
+heuristics I think it should be very exciting.   For me the fundamental Web is
+the Web of people. It's not the Web of  machines talking to each other; it's
+not the network of machines talking to  each other. It's not the Web of
+documents. Remember when machines talked  to each other over some protocol,
+two machines are talking on behalf of two  people. The Consortium has a whole
+technical domain  "Technology and Society"  which recognizes that,  at the end
+of the day, if we're not doing something for the Web of People, then we're
+really not doing something useful at all.</p>
+
+<p>Originally it was social need that drove me to make the Web in the first
+place. In the future one of the exciting things is finding what I call social
+machines. We know about working groups and we know about  social voting
+structures and we know about all sorts of social systems, and  a lot of people
+are very excited about what sort of new social systems we  can make on the
+Web, which maybe can be run by little machines; things that  you can log onto
+and become part of and progress, just as we progress documents along
+standardization tracks, as we endorse things.  We can  invent new forms which
+maybe will allow us to exploit the fact that  we don't have geographical
+boundaries anymore.  I'm very interested in a more fractal, less hierarchical
+structure arising in society, allowing us to operate using the web of trust.
+Perhaps we  can, now that we've got machines that can help us find out
+individually  where we best fit, how we can weave ourselves  into the Web to
+contribute best to society. Maybe we can continue another  very small step
+along that path that we started when we stopped (some of us, most of the time)
+using violence to settle or to decide things, and moved on to using money, or
+in some cases  stopped using money and started actually thinking about what
+other  people were feeling and trying to do, and sharing their goals.  Maybe
+we can find new systems based on peer respect, in which we work together and
+appreciate that we are all in fact trying to go in  the same direction. To me
+that would be very exciting and make the whole  thing worthwhile. Thank you
+very much for your attention.</p>
+
+<p>[Applause.]</p>
+
+<p></p>
+</body>
+</html>

+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
+   "http://www.w3.org/TR/REC-html40/loose.dtd">
+<html>
+<head>
+<title>Web Characterization Terminology &amp; Definitions Sheet</title>
+<link rel="stylesheet" type="text/css"
+href="http://www.w3.org/StyleSheets/TR/W3C-WD">
+</head>
+<body lang="en">
+
+<div class="head">
+
+<a href="http://www.w3.org/"><img src="http://www.w3.org/Icons/w3c_home"
+alt="W3C" height="48" width="72" border="0">
+</a>
+
+<h1>Web Characterization Terminology &amp; Definitions Sheet</h1>
+
+<h2>W3C Working Draft 24-May-1999</h2>
+<dl>
+<dt>This version:</dt>
+<dd>
+<a
+href="http://www.w3.org/1999/05/WCA-terms/01">http://www.w3.org/1999/05/WCA-terms/01</a>
+</dd>
+<dt>Latest version:</dt>
+<dd>
+<a
+href="http://www.w3.org/1999/05/WCA-terms/">http://www.w3.org/1999/05/WCA-terms/</a>
+</dd>
+<dt>Editors:</dt>
+<dd>
+Brian Lavoie &lt;<a href="mailto:lavoie@oclc.org">lavoie@oclc.org</a>>,
+</dd>
+<dd>
+Henrik Frystyk Nielsen &lt;<a href="mailto:frystyk@w3.org">frystyk@w3.org</a>>
+</dd>
+</dl>
+
+<a
+href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a>
+&copy; 1999 <a href="http://www.w3.org/">W3C</a> (<a
+href="http://www.lcs.mit.edu/">MIT</a>, <a
+href="http://www.inria.fr/">INRIA</a>, <a
+href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. W3C <a
+href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
+<a
+href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a>,
+<a href="http://www.w3.org/Consortium/Legal/copyright-documents">document
+use</a> and <a
+href="http://www.w3.org/Consortium/Legal/copyright-software">software
+licensing</a> rules apply.&nbsp;
+<hr title="Separator for header">
+
+</div>
+
+<h2><a name="abstract"></a>Abstract</h2>
+
+In characterizing the structure and content of the Web, it is necessary to
+establish precise semantics for Web concepts. The Web has proceeded for a
+surprisingly long time without consistent definitions for concepts which have
+become part of the common vernacular, such as "Web site" or "Web page". This
+can lead to a great deal of confusion when attempting to develop, interpret,
+and compare Web metrics.
+
+<p>This document represents an effort on the part of the W3C Web
+Characterization Activity to establish a shared understanding of key Web
+concepts. The primary goal in preparing this document was to develop a common
+interpretation for terminology related to Web characterization research.
+However, it is hoped that the Web community at large will also benefit from
+the enumeration and definition of important Web concepts.</p>
+
+<h2><a name="status"></a>Status of this document</h2>
+
+This document is a working draft for review by W3C members and other
+interested parties. It reflects rough consensus of the W3C Web
+Characterization Activity Working Group. We do not claim the set of terms
+defined in this Working Draft to be exhaustive nor (despite our efforts) that
+all definitions are applicable in all situations. The purpose of this Working
+Draft is to bring clarity to the terms often used when talking about the Web
+as well as to encourage discussion of these and other terms. It is expected
+that future changes will be elaborations on the concepts contained in this
+document, rather than changes in the concepts themselves. Please send comments
+to the &lt;<a href="mailto:www-wca@w3.org">www-wca@w3.org</a>> mailing list
+which is archived at "<a
+href="http://lists.w3.org/Archives/Public/www-wca/">http://lists.w3.org/Archives/Public/www-wca/</a><a></a>"
+
+<p>Information on the W3C Web Characterization Activity is located at "<a
+href="http://www.w3.org/WCA/">http://www.w3.org/WCA/</a>". A list of current
+W3C Recommendations and other technical documents can be found at "<a
+href="http://www.w3.org/TR/">http://www.w3.org/TR/</a>".</p>
+
+<h2><a name="contents"></a>Table of contents</h2>
+<dl>
+<dt><a href="#PRIMITIVE">1. Primitive Elements</a></dt>
+<dt><a href="#WEBSCOPE">2. The Scope of the Web from Perspective of Web
+Characterization</a></dt>
+<dd><dl>
+<dt><a href="#WEBCLIENTS">2.1 Web Clients</a></dt>
+<dt><a href="#WEBSERVERS">2.2 Web Servers</a></dt>
+<dt><a href="#RESOURCESTRUCTURE">2.3 Resource Structure</a></dt>
+</dl>
+</dd>
+<dt><a href="#References">3. References</a></dt>
+</dl>
+
+<h2><a name="PRIMITIVE">1. Primitive Elements</a></h2>
+
+Primitive elements are general concepts and terms that can be used to describe
+an information space like the Web. These terms are not necessarily limited to
+resources accessible via any particular access mechanism nor are they
+guaranteed to be accessible via the Internet.
+
+<p>In this context we use them to describe the information space known as
+<em>the Web</em>. However, in addition to illustrating the scope of the Web in
+general, the reason why we mention them here is that they are needed to define
+a more <a href="#WEBSCOPE">restrictive set of terms used in Web
+characterization research</a> which we can measure and define a set of metrics
+for.</p>
+
+<h3><a name="Resource">Resource</a></h3>
+
+<p>The <a href="http://www.rfc-editor.org/rfc/rfc2396.txt">URI
+specification</a> describes a <a
+href="http://www.rfc-editor.org/rfc/rfc2396.txt">resource</a> as the common
+term for "...anything that has identity. Familiar examples include an
+electronic document, an image, a service (e.g., "today's weather report for
+Los Angeles"), as well as a collection of other resources. Not all resources
+are network "retrievable"; e.g., human beings, corporations, and bound books
+in a library can also be considered resources..." (see also the term <a
+href="#Resource2">Web Resource</a>).</p>
+
+<p><em><strong>Examples:</strong> Web page, collection of Web pages, service
+that provides information from a database, e-mail message, Java classes
+...</em></p>
+
+<h3><a name="URI">URI</a></h3>
+
+<p>The <a href="http://www.rfc-editor.org/rfc/rfc2396.txt">URI
+specification</a> defines a <a
+href="http://www.rfc-editor.org/rfc/rfc2396.txt">Uniform Resource Identifier
+(URI)</a> as a compact string of characters for identifying an abstract or
+physical <a href="#Resource">resource</a>.</p>
+
+<h3><a name="Resource1">Resource Manifestation</a></h3>
+
+A resource manifestation is a rendition of a resource at a specific point in
+time and space. A conceptual mapping exists between a resource and a resource
+manifestation (or set of manifestations), in the sense that the resource has
+certain properties - e.g., its URI, its intended purpose, etc. - which are
+inherited by each manifestation, although the specific structure, form, and
+content of the manifestation may vary according to factors such as the
+environment in which it is displayed, the time it is accessed, etc. Regardless
+of the form the manifestation's rendering ultimately takes, the conceptual
+mapping to the resource is preserved.
+
+<p><em><strong>Note:</strong> For historical reasons, HTTP/1.x calls a
+manifestation for an "entity"</em><em>.</em></p>
+
+<p><em><strong>Examples:</strong> real-time information accessed from a news
+Web site on a particular day, up-to-the-minute stock quotes, a rendering of a
+multimedia Web page accessed with a particular client ...</em></p>
+
+<h3><a name="Link">Link</a></h3>
+
+<p>A link expresses one or more (explicit or implicit) relationships between
+two or more resources.</p>
+
+<p><em><strong>Note:</strong> The type of the relationship can describe
+relationships like "authored by", "embedded", etc. Types can themselves be
+identified by URIs as for example is the case for </em><a
+href="/RDF/"><em>RDF</em></a><em>.</em></p>
+
+<p><em><strong>Examples:</strong> An HTML </em><code><em>&lt;a
+href="http://www.w3.org/Protocols/#News">...&lt;/a></em></code><em> element,
+an HTML <code>&lt;img src=&lt;http://www.w3.org/icons/w3c-home"></code>
+element.</em></p>
+
+<h3><a name="Anchor">Anchor</a></h3>
+
+<p>An area within a resource that can be the source or destination of zero,
+one or more <a href="#Link">links</a>. An anchor may refer to the whole
+resource, particular parts of the resource, or to particular manifestations of
+the resource.</p>
+
+<p><em><strong>Examples:</strong> An HTML </em><code><em>&lt;a
+name="http://www.w3.org/Protocols/#News">...&lt;/a></em></code><em>
+element.</em></p>
+
+<h3><a name="Client">Client</a></h3>
+
+The role adopted by an application when it is retrieving and/or rendering
+resources or resource manifestations.
+
+<p><em><strong>Examples:</strong> A Web browser, an e-mail reader, a Usenet
+reader ...</em></p>
+
+<h3><a name="Server">Server</a></h3>
+
+The role adopted by an application when it is supplying resources or resource
+manifestations.
+
+<p><em><strong>Examples:</strong> An HTTP server, a file server, etc
+...</em></p>
+
+<h3><a name="Proxy">Proxy</a></h3>
+
+<p>A proxy is an intermediary which acts as both a server and a client for the
+purpose of retrieving resources or resource manifestations on behalf of other
+clients. Clients using a proxy know the proxy is present and that it is an
+intermediary.</p>
+
+<p><em><strong>Examples:</strong> An HTTP firewall proxy ...</em></p>
+
+<h3><a name="Gateway">Gateway</a></h3>
+
+<p>A gateway is an intermediary which acts as a server on behalf of some other
+server with the purpose of supplying resources or resource manifestations from
+that other server. Clients using a gateway know the gateway is present but
+does not know that it is an intermediary.</p>
+
+<p><em><strong>Examples:</strong> An HTTP to FTP gateway</em></p>
+
+<h3><a name="Message">Message</a></h3>
+
+A unit of communication exchanged between equivalent network layers or
+services, located at different hosts.
+
+<p><em><strong>Examples:</strong> A datagram sent from one Internet layer to
+another, an e-mail sent from one e-mail reader and received at another
+...</em></p>
+
+<h3><a name="Request">Request</a></h3>
+
+A message describing an atomic operation to be carried out in the context of a
+specified resource.
+
+<p><em><strong>Examples:</strong> HTTP GET, POST, PUT, and HEAD requests
+...</em></p>
+
+<h3><a name="Response">Response</a></h3>
+
+A message containing the result of an executed request.
+
+<p><em><strong>Examples:</strong> An HTML document, a server error message
+...</em></p>
+
+<h3><a name="User">User</a></h3>
+
+The principal using a client to interactively retrieve and render resources or
+resource manifestations.
+
+<p><em><strong>Examples:</strong> A person using a Web browser, a person using
+an e-mail reader, a person using a CRT terminal emulator ...</em></p>
+
+<h3><a name="Publisher">Publisher</a></h3>
+
+<p>The principal responsible for the publication of a given resource and for
+the mapping between the resource and any of its resource manifestations. See
+also the term <a href="#site1">Web Site Publisher</a></p>
+
+<p><em><strong>Examples:</strong> A person writing an e-mail message, a person
+composing a Web page</em></p>
+
+<h2><a name="WEBSCOPE">2. The Scope of the Web from the Perspective of Web
+Characterization</a></h2>
+
+<p>The primitive elements defined above are useful when talking about the Web
+in general but are too broad in practice to enable us to characterize the Web
+with the desired level of rigor. This does not mean that we do not consider
+the general terms important or interesting, but that we need a mechanism for
+limiting the scope of the problem of characterizing the Web.</p>
+
+<p>Therefore, we define the following terms to address the question of "What
+is the Web?" from the perspective of Web Characterization. For the purposes of
+Web Characterization research, the Web may be viewed as consisting of three
+components: the core, the neighborhood, and the periphery:</p>
+
+<p style="text-align: center"><img src="Web-WCA" alt="Scope of the Web from
+WCA's perspective"></p>
+
+<p>where</p>
+
+<h3><a name="Core">Web Core</a></h3>
+
+The collection of resources residing on the Internet that can be accessed
+using any implemented version of HTTP as part of the protocol stack (or its
+equivalent), either directly or via an intermediary.
+
+<p><em><strong>Notes:</strong> By the term "or its equivalent" we consider any
+version of HTTP that is currently implemented as well as any new standards
+which may replace HTTP (HTTP-NG, for example). Also, we include any protocol
+stack including HTTP at any level, for example HTTP running over SSL.</em></p>
+
+<h3><a name="Resource2">Web Resource</a></h3>
+
+<p>A resource, identified by a URI, that is a member of the <a
+href="#Core">Web Core</a>.</p>
+
+<p><em><strong>Note:</strong> The URI identifying the Web Resource does not
+itself have to be found within the Web Core. That is, a URI written on a bus
+identifying a resource that is a member of the </em><a href="#Core"><em>Web
+Core</em></a><em> identifies a Web Resource.</em></p>
+
+<h3><a name="Resource3">Web Resource Manifestation</a></h3>
+
+<p>A <a href="#Resource1">resource manifestation</a> generated by a <a
+href="#Resource2">Web resource</a>.</p>
+
+<h3><a name="Neighborho">Web Neighborhood</a></h3>
+
+<p>The collection of <a href="#Resource">resources</a> directly <a
+href="#Link">linked</a> from a <a href="#Resource2">Web resource</a>.</p>
+
+<h3><a name="Web-access">Web Neighborhood Resource</a></h3>
+
+A resource, identified by a URI, that is a member of the <a
+href="#Neighborho">Web Neighborhood</a>.
+
+<p><em><strong>Examples:</strong> An "<code>ftp</code>" link within an HTML
+document which can be accessed via HTTP, a "<code>mailto</code>" link within
+an HTML document which can be accessed via HTTP.</em></p>
+
+<h3><a name="Periphery">Web Periphery</a></h3>
+
+<p>The collection of resources on the Web which is <em>not</em> part of the <a
+href="#Core">Web Core</a> or the <a href="#Neighborho">Web
+Neighborhood</a>.</p>
+
+<h2><a name="WEBCLIENTS">2.1 Web Clients</a></h2>
+
+<p>Concepts relating to the process of accessing Web resources and render <a
+href="#Resource3">Web resource manifestations</a>.</p>
+
+<h3><a name="Client1">Web Client</a></h3>
+
+A client that is capable of accessing Web resources by issuing requests and
+render responses containing Web resource manifestations.
+
+<p><em><strong>Examples:</strong> A Web browser, a harvester, a spider
+...</em></p>
+
+<h3><a name="Click">Web Request</a></h3>
+
+<p>A Web request is a <a href="#Request">request</a> issued by a <a
+href="#Client1">Web client</a>. A Web request can be described as either:</p>
+<dl>
+<dt>Explicit Web request:</dt>
+<dd>
+A request that is initiated manually by the <a href="#User">user</a>.
+</dd>
+<dt>Implicit Web request:</dt>
+<dd>
+A request that is initiated transparently by the <a href="#Client1">Web
+client</a>, without manual intervention on the part of the user, as an
+ancillary event corresponding to an explicit Web request.
+</dd>
+</dl>
+
+<p>and as either:</p>
+<dl>
+<dt>Embedded Web request:</dt>
+<dd>
+A request for dereferencing a URI embedded within a Web resource
+manifestation: e.g., following the <a href="#Link">link</a> in an HTML
+document, etc.
+</dd>
+<dt>User-input Web request:</dt>
+<dd>
+A request for dereferencing a URI supplied by the user directly to the Web
+client: e.g., typed into the address window, bookmarks, history, etc.
+</dd>
+</dl>
+
+<p><strong><em>Examples:</em></strong><em> a) A user follows a link appearing
+in a HTML document (explicit, embedded Web request). The Web client retrieves
+the requested HTML document, and also makes an additional request for an image
+referenced in the HTML document (implicit, embedded Web request); b) A user
+reads the URI printed on a bus and feeds it to the Web client (explicit,
+user-input Web request).</em></p>
+
+<h3><a name="Client2">Web Request Header</a></h3>
+
+<p>The request header contains information about the request, information
+about the client itself, and potentially information about any resource
+manifestation included in the request.</p>
+
+<p><em><strong>Examples:</strong><a href="request.txt"> Sample HTTP request
+header</a></em></p>
+
+<h3 id="Request1">Web Request Body</h3>
+
+<p>The request body (if any) of an HTTP request is used to carry the payload
+of the HTTP message.</p>
+
+<h3><a name="User1">User Session</a></h3>
+
+A delimited set of user clicks across one or more Web servers.
+
+<p><em>Example: At a library, a patron sits down at a public Internet-access
+terminal, accesses one or more Web resources, then relinquishes control of the
+terminal to another patron.</em></p>
+
+<h3><a name="Episode">Episode</a></h3>
+
+A subset of related user clicks that occur within a user session.
+
+<p><em>Example: Continuing the previous example, the library patron accesses a
+weather report (episode 1), checks stock prices (episode 2), then downloads a
+patch for his operating system (episode 3).</em></p>
+
+<h2><a name="WEBSERVERS">2.2 Web Servers</a></h2>
+
+Concepts relating to the process of supplying Web resource manifestations.
+
+<h3><a name="Server3">Web Server</a></h3>
+
+A server that provides access to Web resources and which supplies Web resource
+manifestations to the requestor.
+
+<h3><a name="Response1">Web Response</a></h3>
+
+<p>A Web response is a <a href="#Response">response</a> issued by a <a
+href="#Server3">Web server</a>.</p>
+
+<h3><a name="Server4">Web Response Header</a></h3>
+
+The response header contains information about the response, information about
+the server itself, and potentially information about any resource
+manifestation which may or may not be included in the response.
+
+<p><em><strong>Examples:</strong> <a href="response.txt">Sample HTTP Response
+Header</a></em></p>
+
+<h3><a name="Server5">Web Response Body</a></h3>
+
+The response body (if any) of an HTTP response is used to carry the payload of
+the HTTP message.
+
+<h3><a name="Server1">Server Session</a></h3>
+
+<p>A collection of user clicks to a single Web server during a user session.
+Also called a visit.</p>
+
+<h3><a name="Cookie">Cookie</a></h3>
+
+Data sent by a Web server to a Web client, to be stored locally by the client
+and sent back to the server on subsequent requests.
+
+<p><em>Example: When the Web site of an online retail store is accessed for
+the first time by a particular client, a unique hashcode is sent back to the
+client to be stored locally. Then, when the client requests URLs from the
+site, the hashcode is appended to the URL request, allowing the Web site
+administrators to track the surfing pattern of the customer through the
+site.</em>&nbsp;</p>
+
+<h2><a name="RESOURCESTRUCTURE">2.3 Resource Structures</a></h2>
+
+The following concepts relates to the structure of Web content.
+
+<h3><a name="page">Web page</a></h3>
+
+A collection of information, consisting of one or more Web resources, intended
+to be rendered simultaneously, and identified by a single URI. More
+specifically, a Web page consists of a <a href="#Resource2">Web resource</a>
+with zero, one, or more embedded <a href="#Resource2">Web resources</a>
+intended to be rendered as a single unit, and referred to by the URI of the
+one Web resource which is not embedded.
+
+<p><em><strong>Examples:</strong> An image file, an applet, and an HTML file
+identified and accessed through a single URI, and rendered simultaneously by a
+Web client.</em></p>
+
+<p><em><strong>Note:</strong> The components of a Web page can reside at
+different network locations. The location of the Web page, however, is
+determined by the URI identifying the page.</em></p>
+
+<p><em><strong>Note:</strong> The scope of a Web page is limited to the
+collection of Web resources which are displayed simultaneously by requesting
+the Web page's URI. The components of a Web page actually rendered in a page
+view is client-dependent.</em></p>
+
+<h3><a name="Page">Page View</a></h3>
+
+Visual rendering of a Web page in a specific client environment at a specific
+point in time.
+
+<p><em><strong>Examples:</strong> Displaying a particular Web page in Internet
+Explorer is a pageview; displaying the same page in Netscape Navigator is a
+different page view.</em></p>
+
+<h3><a name="Home">Host Page</a></h3>
+
+A Web page identified by a URI containing an <code>&lt;authority></code>
+component but where the <code>&lt;path></code> component is either empty or
+simply consists of a single <code>"/"</code> only.
+
+<p><em><strong>Examples:</strong> The Web pages identified by
+<code>http://www.w3.org</code> and <code>http://www.cern.ch</code> are host
+pages</em></p>
+
+<h3><a name="site">Web site</a></h3>
+
+A collection of interlinked Web pages, including a <a href="#Home">host
+page</a>, residing at the same network location. "Interlinked" is understood
+to mean that any of a Web site's constituent <a href="#page">Web pages</a> can
+be accessed by following a sequence of references beginning at the site's <a
+href="#Home">host page</a>; spanning zero, one or more <a href="#page">Web
+pages</a> located at the same site; and ending at the Web page in question.
+
+<p><strong><em>Examples:</em></strong><em> The Web page consisting of the
+article "Thought Paper on Automatic Recharacterization" is part of the <a
+href="http://www.w3.org">W3C Web site</a>, since it satisfies the two
+properties mentioned above. First, it resides at the same network location as
+the W3C </em><a href="#Home"><em>host page,</em></a><em>
+</em><code><em>http://www.w3.org</em></code><em>. Second, we can begin at the
+W3C host page (</em><code><em>http://www.w3.org</em></code><em>) and follow a
+sequence of internal links, ending at the article: specifically:</em></p>
+<ol>
+<li>
+<em><code>http://www.w3.org</code> to <code>http://www.w3.org/WCA/</code>,
+and</em>
+</li>
+<li>
+<em><code>http://www.w3.org/WCA/</code> to
+<code>http://www.w3.org/WCA/1998/12/aut_char.html</code></em>
+</li>
+</ol>
+
+<p><em><strong>Notes:</strong> It is not uncommon for Web sites to be
+duplicated, or mirrored, on multiple physical host machines (e.g., for load
+balancing purposes). Typically, it is immaterial to the client (or user) which
+host machine is used to access the Web site.</em><em> In this case, it may be
+useful to consider this collection of "physical" Web sites, located at
+multiple host machines, as one "logical" Web site.</em><em> This is possible
+in the case where a single domain name is mapped to each of the host machines;
+the logical Web site can then be identified using the unique domain name.
+</em><em>If there is no unique domain name that can be applied to the
+collection of duplicate sites, we consider each physical host machine as a
+separate Web site.</em></p>
+
+<h3><a name="Independen">Independent Web Page</a></h3>
+
+A Web page that is not part of the Web site associated with its network
+location. Specifically, it is not possible to reach the Web page in question
+by traversing a sequence of links internal to the Web site, beginning at the
+<a href="#Home">host page</a>.
+
+<p><em><strong>Examples:</strong> If a page is mounted on a Web server, but is
+not linked to by any page on the Web site associated with the server, then the
+page is like an "island" on the Web. The only way the page can be accessed is
+through explicit knowledge of its URI.&nbsp;&nbsp;</em></p>
+
+<h3><a name="site1">Web Site Publisher</a></h3>
+
+A person or corporate body that is the primary claimant to the rewards or
+benefits resulting from usage of the Web site, incurs at least part of the
+costs necessary to produce and distribute the site, and exercises editorial
+control over the finished form of the Web site and its content. See also the
+term <a href="#Publisher">publisher</a>.
+
+<p><em><strong>Examples:</strong> The W3C is the publisher of the site located
+at http://www.w3.org/ ...</em></p>
+
+<h3><a name="Subsite">Subsite</a></h3>
+
+A cluster of Web pages within a Web site, that is maintained by a different
+publisher than that of the parent Web site, or host site. The subsite
+publisher exercises editorial control over the Web pages comprising the
+subsite, perhaps restrained by some broad guidelines imposed by the host site
+publisher.
+
+<p><em><strong>Examples:</strong> An Internet service provider supplying
+hosting services to its customers. All of the customers' Web sites may be
+located at the same IP address, but nevertheless represent logically
+independent sites (and, in the case of virtual hosting, may even have distinct
+domain names).</em></p>
+
+<h3><a name="Collection">Web Collection</a></h3>
+
+A portion or section of a <a href="#site">Web site</a>, consisting of two or
+more Web pages, that represents a non-trivial, self-contained resource, but is
+still maintained by the same publisher of the overall <a href="#site">Web
+site</a>.
+
+<p><em><strong>Examples:</strong> Web journal, electronic monograph, photo
+gallery ...</em></p>
+
+<h3><a name="Supersite">Supersite</a></h3>
+
+A single, logical <a href="#site">Web site</a> that extends over multiple
+network locations, but is intended to be viewed as a single <a
+href="#site">Web site</a>. It is transparent to the user that the site is
+distributed over multiple locations. A single <a href="#Home">host page</a>
+applies to the entire supersite.
+
+<p><em><strong>Examples:</strong> The resources available from a particular
+entity may be distributed over multiple servers, but users access the
+supersite through one <a href="#Home">host page</a>, and view the distributed
+resources as one logical site.</em></p>
+
+<h2><a name="References" href="#contents">4. References</a></h2>
+
+<p>Other useful places to look for terminology sections are</p>
+<ul>
+<li>
+<a href="/Terms">Hypertext terms defined by Tim Berners-Lee in 1995</a>
+</li>
+<li>
+<a href="/Architecture/Terms.html">Another set of hypertext terms defined by
+Dan Connolly in 1996</a>
+</li>
+<li>
+<a
+href="http://www.w3.org/Protocols/HTTP/1.1/draft-ietf-http-v11-spec-rev-06.txt">Hypertext
+Transfer Protocol 1.1 Specification</a>
+</li>
+<li>
+<a href="http://www.w3.org/TR/REC-html40/">Hypertext Markup Language 4.0
+Specification</a>
+</li>
+<li>
+<a href="http://info.internet.isi.edu/in-notes/rfc/files/rfc2396.txt">Uniform
+Resource Identifier Specification</a>
+</li>
+</ul>
+
+<p></p>
+<hr title="Separator from footer">
+
+<address>
+
+<p>@(#) $Id: 01.html,v 1.46 1999/05/24 13:58:18 frystyk Exp $</p>
+</address>
+
+<p></p>
+</body>
+</html>

+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+  <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
+  <META NAME="GENERATOR" CONTENT="Mozilla/4.04 [en] (WinNT; I) [Netscape]">
+  <!-- Created with AOLpress/2.0 -->
+  <STYLE type=text/css>
+        .example {
+        BACKGROUND-COLOR: #f9f5de; BORDER-BOTTOM: 1px solid; BORDER-LEFT: 1px solid; BORDER-RIGHT: 1px solid; BORDER-TOP: 1px solid; COLOR: #5d0091; MARGIN-LEFT: 10%; WIDTH: 65%
+        }
+        img.W3CIcon {
+        BORDER: 0;
+        }       
+</STYLE>
+  <TITLE>CC/PP: A user side framework for enhanced content negotiation</TITLE>
+  <LINK rel="stylesheet" type="text/css" href="http://www.w3.org/StyleSheets/TR/W3C-NOTE">
+</HEAD>
+<BODY>
+<DIV class="head">
+  <IMG src="http://www.w3.org/Icons/WWW/w3c_home" ALT ="W3C" class="W3CIcon">
+  <H1>
+    Composite Capability/Preference Profiles (CC/PP): A user side framework for
+    content negotiation
+  </H1>
+  <H2>
+    W3C Note 27 July 1999
+  </H2>
+  <DL>
+    <DT>
+      This Version:
+    <DD>
+      <A HREF="http://www.w3.org/1999/07/NOTE-CCPP-19990727/">http://www.w3.org/TR/1999/NOTE-CCPP-19990727</A>
+    <DT>
+      Latest Version:
+    <DD>
+      <A HREF="http://www.w3.org/TR/NOTE-CCPP">http://www.w3.org/TR/NOTE-CCPP</A>
+    <DT>
+      Previous version:
+    <DD>
+      <A HREF="http://www.w3.org/TR/1998/NOTE-CCPP-19981130">http://www.w3.org/TR/1998/NOTE-CCPP-19981130</A>
+  </DL>
+  <DL>
+    <DT>
+      Editors
+    <DD>
+      Franklin Reynolds
+      <A HREF="mailto:franklin.reynolds@research.nokia.com">franklin.reynolds@research.nokia.com</A>,
+      Nokia Research Center
+    <DD>
+      Johan Hjelm <A HREF="mailto:hjelm@w3.org">hjelm@w3.org</A>, W3C/Ericsson
+    <DD>
+      Spencer Dawkins <A HREF="mailto:sdawkins@nt.com">sdawkins@nt.com</A>, Nortel
+    <DD>
+      Sandeep Singhal <A HREF="mailto:singhal@us.ibm.com">singhal@us.ibm.com</A>,
+      IBM
+  </DL>
+  <P>
+  <H2>Status of this document</H2>
+  <P>
+  This document is a work in progress, representing a revision of the working
+  draft dated 1998-10-05 incorporating suggestions received in review comments
+  and further deliberations of the W3C Mobile Access Interest Group. It also
+  incorporates suggestions resulting from reviews by members of the IETF CONNEG
+  working group and the WAPForum. It is the first public review draft of this
+  document. Publication as a working draft does not imply endorsement by the
+  W3C membership.
+  <P>
+  All RDF code has been <A HREF="http://jigsaw.w3.org:8000/description">validated
+  </A>with <A HREF="http://www.w3.org/RDF/Implementations/SiRPAC/">SiRPAC</A>,
+  the W3C RDF validator.
+  <P>
+  The RDF code has been updated on July 26, 1999, to reflect the Resource
+  Description Framework (RDF) Model and Syntax Specification Recommendation,
+  and the 3&nbsp;March Resource Description Framework (RDF) Schemas Proposed
+  Recommendation. Minor updates to the text, reflecting the work that has been
+  conducted in the W3C since November 1998, has also been added.
+  <P>
+  Review comments from the public on this document should be sent to
+  <A HREF="mailto:www-mobile@w3.org">www-mobile@w3.org</A> which is an
+  automatically
+  <A HREF="http://lists.w3.org/Archives/Public/www-mobile/">archived</A> email
+  list. Information on how to subscribe to public W3C email lists can be found
+  at <A HREF="http://www.w3.org/Mail/Lists">http://www.w3.org/Mail/Request</A>.
+  <P>
+  <EM>This document is a NOTE made available by the W3 Consortium for discussion
+  only. This indicates no endorsement of its content, nor that the Consortium
+  has, is, or will be allocating any resources to the issues addressed by this
+  NOTE.</EM>
+  <P>
+  <A HREF="http://www.w3.org/Consortium/Legal/ipr-notice.html#Copyright">Copyright</A>
+  &copy; 1997,1998, 1999 <A HREF="http://www.w3.org">W3C</A>
+  (<A HREF="http://www.lcs.mit.edu">MIT</A>,
+  <A HREF="http://www.inria.fr/">INRIA</A>,
+  <A HREF="http://www.keio.ac.jp/">Keio</A> ), All Rights Reserved. W3C
+  <A HREF="http://www.w3.org/Consortium/Legal/ipr-notice.html#LegalDisclaimer">liability</A>,
+  <A HREF="http://www.w3.org/Consortium/Legal/ipr-notice.html#W3CTrademarks">trademark</A>,
+  <A HREF="http://www.w3.org/Consortium/Legal/copyright-documents.html">document
+  use</A> and
+  <A HREF="http://www.w3.org/Consortium/Legal/copyright-software.html">software
+  licensing</A> rules apply.
+</DIV>
+  <H2>
+    Table of Contents
+  </H2>
+  <P>
+  <A HREF="#Abstract">Abstract</A>
+  <P>
+  <A HREF="#1">1. Introduction</A>
+  <P>
+  <A HREF="#11">1.1 Wireless networks</A>
+  <P>
+  <A HREF="#12">1.2 Goals of this work</A>
+  <P>
+  <A HREF="#2">2. Metadata and profiles</A>
+  <P>
+  <A HREF="#3">3. Composite Capability/Preferences Profiles (CC/PP)</A>
+  <P>
+  <A HREF="#31">3.1 Inline example</A>
+  <P>
+  <A HREF="#32">3.2 Indirect references</A>
+  <P>
+  <A HREF="#33">3.3 Runtime changes</A>
+  <P>
+  <A HREF="#4">4. Protocol considerations</A>
+  <P>
+  <A HREF="#5">5. Summary</A>
+  <P>
+  <A HREF="#References">References</A>
+  <H2>
+    <A NAME="Abstract">Abstract</A>
+  </H2>
+  <P>
+  In this note we describe a method for using RDF, the Resource Description
+  Format of the W3C, to create a general, yet extensible framework for describing
+  user preferences and device capabilities. This information can be provided
+  by the user to servers and content providers. The servers can use this
+  information describing the user's preferences to customize the service or
+  content provided. The ability of RDF to reference profile information via
+  URLs assists in minimizing the number of network transactions required to
+  adapt content to a device, while the framework fits well into the current
+  and future protocols being developed a the W3C and the WAP Forum.
+  <H2>
+    <A NAME="1">1. Introduction</A>
+  </H2>
+  <P>
+  This document describes the rationale and design of a profile service to
+  describe the capabilities and preferences of Web enabled applications. A
+  Composite Capability/Preference Profile (CC/PP) is a collection of the
+  capabilities and preferences associated with user and the agents used by
+  the user to access the World Wide Web. These user agents include the hardware
+  platform, system software and applications used by the user. User agent
+  capabilities and references can be thought of as metadata or properties and
+  descriptions of the user agent hardware and software.
+  <P>
+  A description of the user's capabilities and preferences is necessary but
+  insufficient to provide a general content negotiation solution. A general
+  framework for content negotiation requires a means for describing the meta
+  data or attributes and preferences of the user and his/hers/its agents, the
+  attributes of the content and the rules for adapting content to the capabilities
+  and preferences of the user. The current mechanisms, such as accept headers
+  and &lt;alt&gt; tags, are somewhat limited. Future services will be more
+  demanding. For example: the content might be authored in multiple languages
+  with different levels of confidence in the translation and the user might
+  be able to understand multiple languages with different levels of proficiency.
+  To complete the negotiation some rule is needed for selecting a version of
+  the document based on weighing the user's proficiency in different languages
+  against the quality of the documents various translations.
+  <P>
+  This proposal focuses on the design of a user agent profile service based
+  on XML/RDF. RDF, the Resource Description Format
+  [<A HREF="#[RDF]">RDF</A>][<A HREF="#[RDF-Schema]">RDF-Schema</A>], was designed
+  by the W3C consortium. There is a specification that describes how to encode
+  RDF using XML. RDF was designed to describe the machine understandable properties
+  of web content. In this proposal we explore to use of RDF to describe
+  capabilities and preferences associated with a user and the hardware and
+  software agents used to access the web. We expect the use of a common technology
+  to encode metadata describing both content and a user's preferences will
+  encourage the adoption of the technology and simplify the use of metadata
+  in the Web. Hopefully, powerful tools for dealing with XML and RDF, some
+  of which are already under development, will be available.
+  <P>
+  Some potentially complex negotiation may have to take place between the content
+  or the server of the content and the user of the content. For example: the
+  content might be authored in multiple languages with different levels of
+  confidence in the translation and the user might be able to understand multiple
+  languages with different levels of proficiency. Though we hope that the use
+  of RDF to encode the metadata describing the content and the user's preferences
+  will facilitate the development of solutions to these kinds of complex
+  negotiations, the implementation of appropriate rules for the negotiation
+  is left to application developers.
+  <P>
+  Alternate methods for describing the attributes or meta data of documents
+  are under investigation by other organizations such as the IETF Content
+  Negotiation [<A HREF="#CONNEG">CONNEG</A>] working group. Though this proposal
+  is not directly compatible with the IETF CONNEG proposals currently under
+  development, RDF allows the use of multiple vocabularies. Hopefully, this
+  will provide a means for interoperability, at least at the level of attribute
+  vocabularies. The CONNEG working group is also developing a media feature
+  matching algebra. Efforts are underway to insure that the CONNEG algebra
+  and RDF are complementary technologies. In addition to the IETF we are
+  particularly concerned about the WAPForum and ETSI. The success of the CC/PP
+  effort will undoubtedly hinge on our ability to cooperate with those
+  organizations.
+  <H3>
+    <A NAME="11">1.1 Wireless Networks</A>
+  </H3>
+  <P>
+  Compared to the typical wireline data networks available to corporate desktop
+  users, wireless networks are more expensive, provide less bandwidth, with
+  higher latency and less reliability. SMS data service on GSM networks provides
+  22 bytes (!) per second to a typical mobile host. The situation is rapidly
+  changing. Emerging packet oriented, cellular networks, such as CDPD and CDMA,
+  and with packet oriented bearer technologies such as GPRS and EDGE are providing
+  higher bandwidth and lower latency. Within the next decade we should see
+  the deployment of "third generation" cellular networks that provide low latency
+  and megabit bandwidth to mobile hosts.
+  <P>
+  But today's wireless networks are slow and tomorrow's wireless networks will
+  be slow compared to tomorrow's wireline networks. Protocols designed for
+  wireline networks without regard for the limitations of wireless networks
+  often exhibit undesirable behavior when deployed on wireless networks.
+  <P>
+  CC/PPs are intended to provide information necessary to adapt the content
+  and the content delivery mechanisms to best fit the capabilities and preferences
+  of the user and its agents. Protocol design is beyond the scope of this group,
+  however, the use of CC/PPs does have some impact on web protocols and in
+  this section some of those issues are discussed. The design and implementation
+  of HTTP-NG is being actively carried out by another group. In this section
+  we limit our discussion to some of the issues that many need to be considered
+  in HTTPng or similar protocols:
+  <DL>
+    <DT>
+      Profiles can be quite verbose.
+    <DD>
+      We need ways to reduce the overhead for low bandwidth networks like the cell
+      phone network.
+    <DT>
+      CC/PPs should be cacheable on gateways/proxies.
+    <DT>
+      Components used to construct CC/PPs, such as vendor default profiles, should
+      be independently cacheable.
+    <DT>
+      Changes to the active profile should be very lightweight.
+    <DD>
+      We don't want to have to resend the whole profile to turn off sound.
+    <DT>
+      The protocols must be able to exploit gateways and proxies if they exist.
+    <DT>
+      Though vendors may be able to supply URLs that name default profiles, the
+      client devices may store this information in case the vendor site&nbsp; is
+      unreachable for some reason.
+  </DL>
+  <H3>
+    <A NAME="12">1.2 Goals of this work</A>
+  </H3>
+  <P>
+  The goal of this work is to:
+  <DL>
+    <DT>
+      Enhance content negotiation speed through a standardized format for user
+      agent profiles.
+    <DT>
+      Minimize content negotiation transactions through the use of standardized
+      formats and referencing URLs.
+    <DT>
+      Recognize and support the composition of preferences and profiles originating
+      from multiple sources (e.g. hardware vendors, software vendors, users, etc.).
+    <DT>
+      Enable user control over user agent information (e.g. personal preferences,
+      etc.).
+    <DT>
+      Enable the use of compact data formats, such as tokenized XML
+      [<A HREF="#[TokenXML]">TokenXML</A>], for content negotiation.
+    <DT>
+      Support the presence of multiple network elements (proxies, servers, etc.)
+      between the user agent and the origin server.
+  </DL>
+  <P>
+  The data model for the capability and preferences profile is similar to a
+  table of tables. Each individual table roughly compares to a significant
+  hardware or software component. The primary goal is to be able to describe
+  the desired table of tables in an unambiguous and inter operable fashion.
+  Secondary goals include general applicability and good performance.
+  <H2>
+    <A NAME="2">2. Metadata and profiles</A>
+  </H2>
+  <P>
+  In most documents on 3rd generation networks, scenarios are presented where
+  users will want to assert several preferential
+  factors[<A HREF="#IMT-2000">IMT-2000</A>]. Also, mechanisms for this exist
+  [<A HREF="#[Agent-attrib]">Agent-attrib</A>]. The preferences are such as:
+  <DL>
+    <DT>
+      preferred language
+    <DT>
+      sound on/off
+    <DT>
+      images on/off
+    <DT>
+      privacy preferences (like P3P)
+    <DT>
+      scripting on/off
+    <DT>
+      cookies on/off
+    <DT>
+      etc.
+  </DL>
+  <P>
+  They will also want to assert hardware platform attributes, like:
+  <DL>
+    <DT>
+      vendor
+    <DT>
+      model
+    <DT>
+      class of device {phone, pda, printer, etc.}
+    <DT>
+      screen size
+    <DT>
+      colors
+    <DT>
+      available bandwidth
+    <DT>
+      CPU
+    <DT>
+      memory
+    <DT>
+      input device
+    <DT>
+      secondary storage
+    <DT>
+      loudspeaker
+    <DT>
+      etc.
+  </DL>
+  <P>
+  We also expect them to want to assert software defined variables, such as:
+  <DL>
+    <DT>
+      application brand and version
+    <DT>
+      level of HTML support
+    <DT>
+      supported XML vocabularies
+    <DT>
+      Level of CSS support
+    <DT>
+      supported RDF vocabularies
+    <DT>
+      level of WAP support
+    <DT>
+      supported scripting languages(s)
+    <DT>
+      etc.
+  </DL>
+  <P>
+  It is interesting to note that metadata (capabilities and preferences) associated
+  with the device, the software used to access the web and the user of the
+  device could originate from different sources created at different times.
+  The hardware vendor might have profile information available for its products,
+  the software vendor might supply a default profile, and the user's preferences
+  might apply across multiple applications (preferred language) or change during
+  a session (sound on/off). If it is too complex people won't use it and if
+  it too slow people won't use it. The challenge is to provide an efficient
+  mechanism for communicating the profiles for constrained devices, such as
+  smart phones, using slow networks, such as GSM SMS.
+  <H2>
+    <A NAME="3">3. Composite Capability/Preferences Profiles (CC/PP)</A>
+  </H2>
+  <P>
+  The CC/PP proposal describes an interoperable encoding for capabilities and
+  preferences of user agents, specifically web browsers. The proposal is also
+  intended to support applications other than browsers, including email, calendars,
+  etc. Support for peripherals like printers and fax machines will require
+  other types of attributes such as type of printer, location, Postscript support,
+  color, etc. We believe an XML/RDF based approach would be suitable. However,
+  metadata descriptions of devices like printers or fax machines may use a
+  different scheme. Every reasonable effort will be made to provide
+  interoperability other important proposals.
+  <P>
+  The basic data model for a CC/PP is a collection of tables. Though RDF makes
+  modeling a wide range of data structures possible, it is unlikely that this
+  flexibility will used in the creation of complex data models for profiles.
+  In the simplest form each table in the CC/PP is a collection of RDF statements
+  with simple, atomic properties. These tables may be constructed from default
+  settings, persistent local changes or temporary changes made by a user. One
+  extension to the simple table of properties data model is the notion of a
+  separate, subordinate collection of default properties. Default settings
+  might be properties defined by the vendor. In the case of hardware the vendor
+  often has a very good idea of the physical properties of any given model
+  of product. However, the current owner of the product may be able to add
+  options, such as memory or persistent store or additional I/O devices that
+  add new properties or change the values of some original properties. These
+  would be persistent local changes. An example of a temporary change would
+  be turning sound on or off.
+  <P>
+  The profile is associated with the current network session or transaction.
+  Each major component may have a collection of attributes or preferences.
+  Examples of major components are the hardware platform upon which all the
+  software is executing, the software platform upon which all the applications
+  are hosted and each of the applications. This following is a simplified example
+  of the sort of data expected to be encoded in these profiles.
+  <P>
+  <B>Hardware Platform</B>
+  <P>
+  Memory = 64mb
+  <P>
+  CPU = PPC
+  <P>
+  Screen = 640*400*8
+  <P>
+  BlueTooth = Yes
+  <P>
+  <B>Software Platform</B>
+  <P>
+  OS version = 1.0
+  <P>
+  HTML version = 4.0
+  <P>
+  WML version = 1.0
+  <P>
+  Sound = ON
+  <P>
+  Images = Yes
+  <P>
+  <B>Email</B>
+  <P>
+  Language = English
+  <P>
+  ...
+  <P>
+  Some collections of properties and property values may be common to a particular
+  component. For example: a specific model of a smart phone may come with a
+  specific CPU, screen size and amount of memory by default. Gathering these
+  "default" properties together as a distinct RDF resource makes it possible
+  to independently retrieve and cache those properties. A collection of "default"
+  properties is not mandatory, but it may improve network performance, especially
+  the performance of relatively slow wireless networks.
+  <P>
+  Any RDF graph consists of nodes, arcs and leafs. Nodes are resources, arcs
+  are properties and leafs are property values. An RDF graph based on the previous
+  example that includes "Default" properties for each major component is relatively
+  straightforward.
+  <P>
+  <IMG HEIGHT=432 WIDTH=528 SRC="CCPP-WD-IMG.gif" ALT="">
+  <P>
+  The introduction of "Defaults" makes the graph of each major component more
+  of a simple tree than a table. In this example the major components are
+  associated with the current network session. In this case, the network session
+  is serving as the root of a tree that includes the trees of each major component.
+  RDF was originally intended to describe metadata associated with documents
+  or other objects that can be named via a URI. The closest thing to a "document"
+  associated with a CC/PP is the current network session.
+  <P>
+  From the point of view of any particular network transaction the only property
+  or capability information that is important is whatever is "current". The
+  network transaction does not care about the differences between defaults
+  or persistent local changes, it only cares about the capabilities and preferences
+  that apply to the current network transaction. Because this information may
+  originate from multiple sources and because different parts of the capability
+  profile may be differentially cached, the various components must be explicitly
+  described in the network transaction.
+  <P>
+  The CC/PP is the encoding of profile information that needs to be shared
+  between a client and a server, gateway or proxy. The persistent encoding
+  of profile information and the encoding for the purposes of interoperability
+  (communication) need not be the same. In this document we consider the use
+  of XML/RDF as the interoperability encoding. Persistent storage of profile
+  information is left to the individual applications.
+  <H3>
+    <A NAME="31">3.1 Inline example</A>
+  </H3>
+  <P>
+  Consider a more realistic example of inline encoding of a CC/PP for a
+  hypothetical smart phone. This is an example of the type of information a
+  phone might provide to a gateway/proxy/server. Note that we do not explicitly
+  name the "current network session". Instead, the profiles of each major component
+  is collected in a "Bag". This is probably not necessary since the document
+  in question, the network session, is unlikely to contain additional RDF.
+  <PRE>&lt;?xml version="1.0"?&gt;
+&lt;rdf:RDF
+xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+xmlns:prf="http://www.w3.org/TR/WD-profile-vocabulary#"&gt;
+&nbsp;&lt;rdf:Description about="HardwarePlatform"&gt;
+&nbsp; &nbsp;&lt;prf:Defaults
+&nbsp; &nbsp; Vendor="Nokia"
+&nbsp; &nbsp; Model="2160"
+&nbsp; &nbsp; Type="PDA"
+&nbsp; &nbsp; ScreenSize="800x600x24"
+&nbsp; &nbsp; CPU="PPC"
+&nbsp; &nbsp; Keyboard="Yes"
+&nbsp; &nbsp; Memory="16mB"
+&nbsp; &nbsp; Bluetooth="YES"
+&nbsp; &nbsp; Speaker="Yes" /&gt;
+&nbsp; &lt;prf:Modifications
+&nbsp; &nbsp; Memory="32mB" /&gt;
+&nbsp;&lt;/rdf:Description&gt;
+&nbsp;&lt;rdf:Description about="SoftwarePlatform"&gt;
+&nbsp; &lt;prf:Defaults
+&nbsp; &nbsp;OS="EPOC1.0"
+&nbsp; &nbsp;HTMLVersion="4.0"
+&nbsp; &nbsp;JavaScriptVersion="4.0"
+&nbsp; &nbsp;WAPVersion="1.0"
+&nbsp; &nbsp;WMLScript="1.0" /&gt;
+&nbsp; &lt;prf:Modifications
+&nbsp; &nbsp;Sound="Off"
+&nbsp; &nbsp;Images="Off" /&gt;
+&nbsp;&lt;/rdf:Description&gt;
+&nbsp;&lt;rdf:Description about="EpocEmail1.0"&gt;
+&nbsp; &nbsp;&lt;prf:Defaults
+&nbsp; &nbsp;HTMLVersion="4.0" /&gt;
+&nbsp;&lt;/rdf:Description&gt;
+&nbsp; &lt;rdf:Description about="EpocCalendar1.0"&gt;
+&nbsp; &lt;prf:Defaults
+&nbsp; &nbsp;HTMLVersion="4.0" /&gt;
+&nbsp;&lt;/rdf:Description&gt;
+&nbsp; &lt;rdf:Description about="UserPreferences"&gt;
+&nbsp;&lt;prf:Defaults
+&nbsp; &nbsp; &nbsp; &nbsp; Language="English"/&gt;
+&nbsp;&lt;/rdf:Description&gt;
+&lt;/rdf:RDF&gt;
+
+</PRE>
+  <P>
+  This sample profile is a collection of the capabilities and preferences
+  associated with either a user or the hardware platform or a software component.
+  Each collection of capabilities and preferences are organized within a
+  description block. These description blocks may contain subordinate description
+  blocks to describe default attributes or other collections of attributes.
+  <P>
+  There is nothing that prevents the use of multiple namespaces. This might
+  be useful to either define experimental or non-standard attributes or to
+  define application specific capabilities and preferences.
+  <P>
+  Delivering all of the CC/PP at one time, inline makes some simplifications
+  possible. If the user has overridden some default property, then there is
+  no reason to send the default - all that is needed is to send the current
+  value for that attribute. In the example above, there is no reason to send
+  the hardware platform's default setting of "Memory=16mb" since the user has
+  upgraded the memory to 32mb.
+  <P>
+  The significance of an attribute is generally limited to the component it
+  is describing. For example, each software application can define a value
+  for a "Version" attribute. This indicates the version of the particular
+  application being described. In general, side effects that extend beyond
+  the bounds of a particular component are not defined in this document. The
+  relationship between components is system and application dependent.
+  <P>
+  The major disadvantage of this format is that it is verbose. Some networks
+  are very slow and this would be a moderately expensive way to handle metadata.
+  There are several optimizations possible to help deal network performance
+  issues. One strategy is compressed form of XML
+  [<A HREF="#[TokenXML]">TokenXML</A>] and a complementary strategy is to use
+  indirect references.
+  <H3>
+    <A NAME="32">3.2 Indirect References</A>
+  </H3>
+  <P>
+  Instead of enumerating each set of attributes, a remote reference can be
+  used to name a collection of attributes such as the hardware platform defaults.
+  This has the advantage of enabling the separate fetching and caching of
+  functional subsets. This might be very nice if the link between the gateway
+  or the proxy and the client agent was slow and the link between the gateway
+  or proxy and the site named by the remote reference was fast - a typical
+  case when the user agent is a smart phone. Another advantage is the
+  simplification of the development of different vocabularies for hardware
+  vendors and software vendors (assuming this is a good thing).
+  <P>
+  The following example uses indirect references. First the profile provided
+  by the user agent. It refers to default profiles provided by the hardware
+  and software platform vendors:
+  <P>
+  <TT>-----------------------------------</TT> <BR>
+  <PRE>&lt;?xml version="1.0"?&gt;
+&lt;rdf:RDF
+xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+xmlns:prf="http://www.w3.org/TR/WD-profile-vocabulary#"&gt;
+  &lt;rdf:Description about="HardwarePlatform"&gt;
+      &lt;prf:Defaults&gt;
+            &lt;rdf:li resource="http://www.nokia.com/profiles/2160"/&gt;
+      &lt;/prf:Defaults&gt;
+       &lt;prf:Modifications 
+            Memory="32mB"/&gt;
+   &lt;/rdf:Description&gt;
+   &lt;rdf:Description about="SoftwarePlatform"&gt;
+     &lt;prf:Defaults&gt;
+            &lt;rdf:li resource="http://www.symbian.com/profiles/pda"/&gt;
+     &lt;/prf:Defaults&gt;
+     &lt;prf:Modifications 
+            Sound="Off"
+            Images="Off" /&gt;
+   &lt;/rdf:Description&gt;
+   &lt;rdf:Description about="EpocEmail"&gt;
+&nbsp;&nbsp;  &nbsp;&lt;prf:Defaults&gt;
+            &lt;rdf:li resource="http://www.symbian.com/epoc/profiles/epocemail" /&gt;
+     &lt;/prf:Defaults&gt;
+   &lt;/rdf:Description&gt;
+&nbsp;  &lt;rdf:Description about="EpocCalendar"&gt;
+&nbsp;&nbsp;&nbsp;  &lt;prf:Defaults&gt;            
+           &lt;rdf:li resource="http://www.symbian.com/epoc/profiles/epoccal"/&gt;
+     &lt;/prf:Defaults&gt;
+   &lt;/rdf:Description&gt;
+&nbsp;  &lt;rdf:Description about="UserPreferences"&gt;
+    &lt;prf:Defaults 
+     Language="English" /&gt;
+&lt;/rdf:Description&gt;
+&lt;/rdf:RDF&gt;
+</PRE>
+  <P>
+  -----------------------------------------------------
+  <P>
+  Next, the profile provided by the hardware vendor.
+  <P>
+  ----------------------------------------------------- <BR>
+  <PRE>&lt;?xml version="1.0"?&gt;
+&lt;rdf:RDF
+xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"&gt;
+&lt;rdf:Description
+Vendor="Nokia"
+Model="2160"
+Type="PDA"
+ScreenSize="800x600x24"
+CPU="PPC"
+Keyboard="Yes"
+Memory="16mB"
+Bluetooth="YES"
+Speaker="Yes" /&gt;
+&lt;/rdf:RDF&gt;
+</PRE>
+  <P>
+  -----------------------------------------------------
+  <P>
+  Finally, the profiles provided by the software platform and application vendors.
+  <P>
+  ----------------------------------------------------- <BR>
+  <PRE>&lt;?xml version="1.0"?&gt;
+&lt;rdf:RDF
+xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"&gt;
+&lt;rdf:Description
+OS="EPOC1.0"
+HTMLVersion="4.0"
+JavaScriptVersion="4.0"
+WAPVersion="1.0"
+WMLScript="1.0" /&gt;
+&lt;/rdf:RDF&gt;
+<TT>-----------------------------------------------------------------------</TT>
+</PRE>
+  <PRE>
+&lt;?xml version="1.0"?&gt;
+&lt;rdf:RDF 
+xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"&gt;
+&lt;Description
+&nbsp;&nbsp;&nbsp; Version="EpocEmail1.0"
+&nbsp;&nbsp;&nbsp; HTMLVersion="4.0" /&gt;
+&lt;/rdf:RDF&gt;
+</PRE>
+  <P>
+  <TT>------------------------------------------------------------------------</TT>
+  <PRE>
+&lt;?xml version="1.0"?&gt;
+&lt;rdf:RDF 
+xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"&gt;
+&lt;Description
+&nbsp;&nbsp;&nbsp; Version="EpocCalendar1.0"
+&nbsp;&nbsp;&nbsp; HTMLVersion="4.0" /&gt;
+&lt;/rdf:RDF&gt;
+</PRE>
+  <P>
+  <TT>-----------------------------------------------------</TT>
+  <P>
+  All we did in the second example was group different collections of default
+  attributes together in such a way that they could be named by a URL. Since
+  the hardware and software platform default profiles were independently described
+  using a URL, they can be separately fetched and cached. When an application
+  in the server/gateway/proxy uses RDF to process the CC/PP it may encounter
+  attrributes with default values and user specified values. It is up the
+  application to enforce the rule that user specified attributes over ride
+  default values. RDF does not provide a convenient mechanism for implementing
+  that rule.
+  <H3>
+    <A NAME="33">3.3 Runtime Changes</A>
+  </H3>
+  <P>
+  It is worth noting again that the information we are most concerned with
+  is the <B>current</B> profile. Default properties might have some importance,
+  for example, they may be worth caching independently of any particular session
+  or user. However, the key is for the client and the server/gateway/proxy
+  to have a consistent view of the current profile.
+  <P>
+  It is important to be able to add to and modify attributes associated with
+  the current CC/PP. We need to be able to modify the value of certain attributes,
+  such as turning sound on and off and we need to make persistent changes to
+  reflect things like a memory upgrade. We need to be able to override the
+  default profile provided by the vendor. However, we only need to concern
+  ourselves with changes to the current profile. Reflecting changes to preferences
+  or capabilities in persistent storage is beyond the scope of this document.
+  <P>
+  Our problem is to propogate changes to the current CC/PP to the
+  server/gateway/proxy. One solution is to transmit the entire CC/PP with each
+  change. It would replace the previous profile. This is not ideal for slow
+  networks. An alternative is to send only the changes. Thus if Sound were
+  to be changed from "Off" to "On" the only data that would need to be sent
+  would be:
+  <P>
+  &lt;?xml version="1.0"?&gt;
+  <P>
+  &lt;rdf:RDF
+  <P>
+  xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+  <P>
+  xmlns:prf="http://www.w3C.org/TR/WD-profile-vocabulary#"&gt;
+  <P>
+  &nbsp; &lt;Description about="SoftwarePlatform"
+  <P>
+  &nbsp;&nbsp;&nbsp; Sound="On" /&gt;
+  <P>
+  &lt;/rdf:RDF&gt;&nbsp;
+  <P>
+  Alternatively, the <TT>&lt;Modifications&gt;</TT> element could be used to
+  communicate changes.
+  <H2>
+    <A NAME="4">4. Protocol considerations</A>
+  </H2>
+  <P>
+  When used in the context of a web browsing application, a CC/PP should be
+  associated with a notion of a current session rather than a user or a node.
+  HTTP and WSP (the WAP session protocol) both define different session semantics.
+  The client, server and and gateways and proxies may already have their own,
+  well defined notions of what constitutes a connection or a session. Our protocol
+  strategy is to send as little information as possible and if anyone is missing
+  something, they have to ask for it. If there is good reason to believe that
+  someone is going to ask for a profile, the client can elect to send the most
+  efficient form of the profile that makes sense.
+  <P>
+  Consider the following possible interaction between a server and a client.
+  When the Client begins a session it sends a minimal profile using as much
+  indirection as possible.&nbsp; If the server/gateway/proxy does not have
+  a CC/PP for this session, then it asks for one. When a profile is sent the
+  client tries a minimal form, i.e., it uses as much indirection as possible
+  and only names the non default attributes of the profile. The
+  server/gateway/proxy can try to fill in the profile using the indirect HTTP
+  references (which may be independently cached). If any of these fail, a request
+  for additional data can be sent to the user which can reply with a fully
+  enumerated profile. If the client changes the value of an attribute, such
+  as turning sound off, only that change needs to be sent.
+  <P>
+  It is likely that servers and gateways/proxies will be concerned with different
+  preferences. For example, the server may need to know which language the
+  user prefers and the gateway may have responsibility to trim images to 8
+  bits of color (to save bandwidth). However, the exact use of profile information
+  by each server/gateway/proxy is hard to predict. Therefore gateways/proxies
+  should forward all profile information to the server. Any requests for profile
+  information that the gateway/proxy cannot satisfy should be forwarded to
+  the client.
+  <P>
+  The ability to compose a profile from sources provided by third parties at
+  run-time exposes the system to a new type of attack. For example, if the
+  URL that named the hardware default platform defaults were to be compromised
+  via an attack on DNS it would be possible to load incorrect profile information.
+  If cached within a server/gateway/proxy this could be a serious denial of
+  service attack. If this is a serious enough problem it may be worth adding
+  digital signatures to the URLs used to refer to profile components.
+  <P>
+  New versions of HTTP such as HTTPng should be able to support the CC/PP framework
+  without difficulty. HTTP 1.0 servers and proxies may not be able to handle
+  CC/PPs. Clients need to be able to detect communication with old servers
+  and adapt the protocol accordingly. HTTP 1.1, perhaps via the Mandatory/Optional
+  Extension Framework should be able to support sessions and profiles. At the
+  least, 1.1 proxy servers should pass requests that include CC/PPs on to servers
+  in the hope that the servers will understand the requests. New versions of
+  1.1 proxies and servers should be able to use CC/PPs.
+  <P>
+  This protocol discussion is not a specific proposal for HTTP or WSP. Its
+  intent is merely to illustrate how the design allows us to exploit the
+  cachability of both the current session state and the default profiles.
+  <P>
+  Since the original writing of this document, a W3C Note has been produced,
+  which describes how to use the HTTP 1.1 extension framework to implement
+  a mechanism for communicating CC/PP profiles and profile differences. See
+  the note, <A HREF="http://www.w3.org/TR/NOTE-CCPPexchange">CC/PP exchange
+  protocol based on HTTP Extension Framework</A> <A HREF="# [Ohto]">[Ohto]</A>,
+  for more information.
+  <H2>
+    <A NAME="5">5. Summary</A>
+  </H2>
+  <P>
+  In this document, we have described a proposal for the use of XML/RDF to
+  describe user preferences and the capabilities of the device and software
+  used to access the Web. Encodings of hypothetical user profiles were used
+  to illustrate some of the benefits of RDF. Some of the possible ramifications
+  for Web protocol design were discussed.
+  <H2>
+    <A NAME="References">References</A>
+  </H2>
+  <P>
+  <A NAME="[Agent-attrib]">[Agent-attrib]</A>
+  <A HREF="http://www.w3.org/TR/NOTE-agent-attributes">Client-Specific Web
+  Services by Using User Agent Attributes. Tomihisa Kamada, Tomohiko Miyazaki.
+  W3C Note.</A>
+  <P>
+  <A NAME="[CONNEG]">[CONNEG]</A>
+  <A HREF="http://www.ietf.org/html.charters/conneg-charter.html">IETF working
+  group on content negotiation</A>
+  <P>
+  <A NAME="[IMT-2000]">[IMT-2000]</A> <A HREF="http://www.imt-2000.com">Ericsson
+  in Wideband Wireless Multimedia</A>.
+  <P>
+  <A NAME="[MIME]">[MIME]</A>
+  <A HREF="http://info.internet.isi.edu:80/in-notes/rfc/files/rfc2045.txt">RFC
+  2045 Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet
+  Message Bodies, Borenstein N., Freed N., 1996/11/27</A>
+  <P>
+  <A NAME="[Ohto]">[Ohto]
+  </A><A HREF="http://www.w3.org/TR/NOTE-CCPPexchange">CC/PP exchange protocol
+  based on HTTP Extension Framework</A>
+  <P>
+  <A NAME="[RDF]">[RDF]</A>
+  <A HREF="http://www.w3.org/TR/WD-rdf-syntax/">Resource Description Framework,
+  (RDF) Model and Syntax Specification. Lassila O., Swick R. W3C Working
+  Draft.</A>
+  <P>
+  <A NAME="[RDF-Schema]">[RDF-Schema]</A>
+  <A HREF="http://www.w3.org/TR/WD-rdf-schema/">Resource Description Framework
+  (RDF) Schema Specification. Brickley, D., Guha, R.V. , Layman, A., W3C Working
+  Draft.</A>
+  <P>
+  <A NAME="[TokenXML]">[TokenXML]</A>
+  <A HREF="http://www1.wapforum.org/tech/terms.asp?doc=SPEC-WBXML-19990616.pdf">Binary
+  XML Content Format Specification</A>
+</BODY></HTML>

+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
+   "http://www.w3.org/TR/REC-html40/loose.dtd">
+<html lang="en">
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<meta name="PRAGMA" content="no-cache">
+<meta name="RCS-Id" content="$Id: Overview.html,v 1.6 1999/07/09 17:42:28 renaudb Exp $">
+<title>Mathematical Markup Language (MathML) 1.01 Specification</title>
+<link rel="stylesheet" type="text/css" media="screen" 
+      href="/StyleSheets/TR/W3C-REC.css">
+</head>
+<body>
+
+<div class="head">
+
+<a href="http://www.w3.org/"><img height="48" width="72"
+alt="W3C" src="/Icons/w3c_home.gif"></a>
+
+<h1>Mathematical Markup Language (MathML<sup>&#8482;</sup>) 1.01
+Specification</h1>
+
+<h2>W3C Recommendation, revision of 7 July 1999</h2>
+
+<p>
+<I>REC-MathML-19980407; revised 19990707</I>
+</p>
+
+<dl>
+<dt>This version:</dt>
+<dd>
+<a href="http://www.w3.org/1999/07/REC-MathML-19990707">http://www.w3.org/1999/07/REC-MathML-19990707</a>
+</dd>
+<dt>Latest version:</dt>
+<dd>
+<a href="http://www.w3.org/TR/REC-MathML">http://www.w3.org/TR/REC-MathML</a>
+</dd>
+<dt>Previous version:</dt>
+<dd>
+<a href="http://www.w3.org/TR/1998/REC-MathML-19980407">http://www.w3.org/TR/1998/REC-MathML-19980407</a>
+</dd>
+<dt>Editors:</dt>
+<dd>
+Patrick Ion <a href="mailto:ion@ams.org">&lt;ion@ams.org></a><br>
+(Mathematical Reviews / American Mathematical Society) <br>
+</dd>
+<dd>
+Robert Miner <a
+href="mailto:rminer@geomtech.com">&lt;rminer@geomtech.com></a><br>
+(Geometry Technologies, Inc.) <br>
+</dd>
+<dt>Principal Writers:</dt>
+<dd>
+Stephen Buswell, Stan Devitt, Angel Diaz, Patrick Ion, Robert
+Miner,<br>
+Nico Poppelier, Bruce Smith, Neil Soiffer, Robert Sutor, Stephen Watt
+</dd>
+</dl>
+
+<p class="copyright"><a
+href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright"><br>
+Copyright</a> &copy; 1999 <a href="http://www.w3.org/">W3C</a> (<a
+href="http://www.lcs.mit.edu/">MIT</a>, <a
+href="http://www.inria.fr/">INRIA</a>, <a
+href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. W3C
+<a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
+<a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a>,
+<a href="http://www.w3.org/Consortium/Legal/copyright-documents">document
+use</a> and
+<a href="http://www.w3.org/Consortium/Legal/copyright-software">software
+licensing</a> rules apply.</p>
+<hr title="Separator for header">
+
+</div>
+
+<h2><a name="abstract">Abstract</a></h2>
+
+<p>This specification defines the Mathematical Markup
+Language, or 
+<acronym title="Mathematical Markup Language">MathML</acronym>.  
+MathML is an XML application for describing mathematical
+notation and capturing both its structure and content. The
+goal of MathML is to enable mathematics to be served,
+received, and processed on the Web, just as 
+<acronym title="Hypertext Markup Language">HTML</acronym> 
+has enabled this functionality for text.</p>
+
+<p>This specification of the markup language MathML is
+intended primarily for a readership consisting of those who
+will be developing or implementing renderers or editors using
+it, or software that will communicate using MathML as a
+protocol for input or output. It is not a User's Guide but
+rather a reference document.</p>
+
+<p>This document begins with background information on
+mathematical notation, the problems it poses, and the
+philosophy underlying the solutions MathML proposes.  MathML
+can be used to encode both mathematical notation and
+mathematical content.  Twenty-eight of the MathML tags
+describe abstract notational structures, while another
+seventy-five provide a way of unambiguously specifying the
+intended meaning of an expression.  Additional chapters
+discuss how the MathML content and presentation elements
+interact, and how MathML renderers might be implemented and
+should interact with browsers.  Finally, this document
+addresses the issue of MathML entities (extended characters)
+and their relation to fonts.</p>
+
+<p>While MathML is human-readable it is anticipated that, in
+all but the simplest cases, authors will use equation
+editors, conversion programs, and other specialized software
+tools to generate MathML. Several early versions of such
+MathML tools already exist, and a number of others, both
+freely available software and commercial products, are under
+development.</p>
+
+<h2><a name="status">Status of this document</a></h2>
+
+<p>This document has been reviewed by 
+<acronym title="World Wide Web Consortium">W3C</acronym>
+Members and other interested parties and has been endorsed by
+the Director as a W3C Recommendation. It is a stable document
+and may be used as reference material or cited as a normative
+reference from another document. W3C's role in making the
+Recommendation is to draw attention to the specification and
+to promote its widespread deployment. This enhances the
+functionality and interoperability of the Web.</p>
+
+<p>The fundamental 
+<a href="http://www.w3.org/pub/WWW/TR/REC-xml">eXtensible Markup
+Language 
+(<acronym title="Extensible Markup
+Language">XML</acronym>)</a> 
+1.0 specification upon which MathML is based has been adopted
+as a W3C Recommendation.  Should future changes in the XML
+specification necessitate changes in the MathML specification,
+it is the intention of the W3C Math Working Group to issue a
+revision of the MathML specification.  However, any changes
+are very unlikely to be substantial.</p>
+
+<p>Most of this document represents technology tested by multiple
+implementations.  A summary of MathML rendering and authoring software
+is described on the <a href="http://www.w3.org/Math">W3C Math Working
+Group</a> home page.</p>
+
+<p>The <a href="http://lists.w3.org/Archives/Public/www-math">www-math</a>
+mailing list is a public forum for questions and comments about MathML
+and issues related to putting math on the Web.</p>
+
+<P>The W3C Math Working Group intends further development of
+recommendations for mathematics on the Web, as set out 
+<a href="chapter1.html#goals">below</a>.</p>
+
+<p>A list of current W3C Recommendations and other technical reports
+can be found at <a href="http://www.w3.org/TR">http://www.w3.org/TR</a>.</P>
+
+<p><em>This document is a revised version of the document first released
+on 7 April 1998. <a href="appendixG.html">Changes from the original
+version</a> are only editorial in nature.  The present W3C Math
+Working Group is working on further improvements of MathML.</em></p>
+
+
+<h3>Available formats</h3>
+<p>The MathML 1.01 W3C Recommendation is made available in different formats
+from the <a HREF="http://www.w3.org/Math">W3C Math WG's site</A>.  In case
+of a discrepancy between any of the derived forms and that found in
+the W3C's archive of Recommendations the definitive version is naturally
+the Recommendation.  At first it is expected that zipped and gzipped
+bundles will be made available, but such easily printable formats as
+PostScript or PDF may be supplied.</p>
+
+<h3>Available languages</h3> 
+
+<p>The English version of this specification is the only normative
+version. However, for translations of this document, see 
+<a href="http://www.w3.org/MarkUp/mathml101-updates/translations.html">
+http://www.w3.org/MarkUp/mathml101-updates/translations.html</a>.
+</p> 
+
+
+<h3>Errata</h3>
+
+<dl>
+<dt>The list of known errors in this specification is available at:
+<dd><a href="http://www.w3.org/MarkUp/mathml101-updates/errata.html">
+http://www.w3.org/MarkUp/mathml101-updates/errata.html</a>.
+</dl>
+
+<p>Please report errors in this document to <a
+href="mailto:www-math@w3.org">www-math@w3.org</a>. 
+</p>
+
+<h2><a name="contents">Table of contents</a></h2>
+
+
+<p><a href="toc.html"><b>Extended Table of Contents</b></a></p>
+
+<ul>
+<li><a href="chapter1.html">Chapter 1. Introduction</a></li>
+<li><a href="chapter2.html">Chapter 2. MathML Fundamentals</a></li>
+<li><a href="chap3_1.html">Chapter 3. Presentation Markup</a></li>
+<li><a href="chap4_1.html">Chapter 4. Content Markup</a></li>
+<li><a href="chapter5.html">Chapter 5. Mixing Presentation and Content </a></li>
+<li><a href="chapter6.html">Chapter 6. Entities, Characters and Fonts</a></li>
+<li><a href="chapter7.html">Chapter 7. Implementing MathML</a></li>
+</ul>
+
+<ul>
+<li><a href="appendixA.html">Appendix A. 
+<acronym title="Document Type Definition">DTD</acronym>
+ for MathML</a></li>
+<li><a href="appendixB.html">Appendix B. Glossary</a></li>
+<li><a href="appendixC.html">Appendix C. Operator Dictionary</a></li>
+<li><a href="appendixD.html">Appendix D. Working Group Membership</a></li>
+<li><a href="appendixE.html">Appendix E. Informal 
+<acronym title="Extended Backus-Naur Form">EBNF</acronym>
+Grammar for Content Elements</a></li>
+<li><a href="appendixF.html">Appendix F. Default Semantic Bindings for
+Content Elements</a></li>
+<li><a href="appendixG.html">Appendix G. MathML 1.0 Changes</a></li>
+</ul>
+<ul>
+<li><a href="refs.html">References</a></li>
+</ul>
+
+
+</body>
+</html>
+

+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
+                      "http://www.w3.org/TR/REC-html40/loose.dtd">
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+  <title>Tim Berners-Lee</title>
+  <style type="text/css">
+H1 { font-size: 14pt; font-style: italic}</style>
+</head>
+
+<body bgcolor="white" text="black" link="blue" vlink="green"
+style="color: #000000;background-color: #FFFFFF">
+<p></p>
+
+<h1>D.M. Sendall</h1>
+
+<p>Mike Sendall, my friend and supervisor at CERN, died on Thursday July 15,
+1999  after a valiant struggle with cancer. His brightness and wisdom  and
+great  personal warmth gave very much to everyone he met. He was a wonderful
+person.</p>
+
+<p>Mike was very astute,  always one to spot the flaw no one else had spotted
+in a technical argument, but also posessed of a diplomacy when it came to
+pointing it out.</p>
+
+<p>He was also the English  gentleman. I understood that once he had arrived
+at Heathrow having forgotten his passport.  When the immigration authorities
+asked him how they were to believe who he was, I can imagine him replying "Ah
+yes-- how indeed?" and them letting him through at once.</p>
+
+<p>It was Mike who went along with my idea of getting one of the  "NeXT"
+machines, and Mike who suggested that I could go ahead and use it to play
+with the idea of that global hypertext thing I had been talking about.  When
+Robert Cailliau and I could not figure out how to run the World Wide Web
+project between the two different divisions we were in, Mike advised us how
+to continue.</p>
+
+<p>I think I remember best his quiet smile and that omnipresent twinkle in
+his eye. I'll miss him.</p>
+<address>
+  Tim Berners-Lee
+</address>
+
+<p></p>
+<hr>
+
+<p></p>
+
+<p><i>$Id: dms.html,v 1.4 2003/03/10 15:10:16 amy Exp $</i></p>
+
+<p></p>
+</body>
+</html>

+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
+                      "http://www.w3.org/TR/REC-html40/loose.dtd">
+<html>
+<head>
+  <title>The essentials of a specification - Tim BL</title>
+  <link rel="stylesheet" href="/StyleSheets/base.css">
+  <!-- Changed by: tbl 19990524 -->
+</head>
+
+<body lang="en">
+<p><a href="../"><img alt="W3" border="0" src="/Icons/WWW/w3c_home" width="72"
+height="48"></a></p>
+
+<h1>The essentials of a specification</h1>
+
+<blockquote>
+  <p>This note is a little <em>motherhood and apple pie</em> about how a
+  specification should be couched so as to clearly add a new well-defined
+  piece to the technology.</p>
+</blockquote>
+
+<p>A technical specification defines something.  The document must  specify
+the thing being defined as well as give its definition: a "left hand side" as
+well as a "right hand side".  Both must be done quite precisely.</p>
+
+<p>Typically, technical specifications for the web specify a language  or a
+protocol.  A protocol is a language for messages, plus a set of constraints on
+the sequence of messages. A language is a set of symbols, the syntactic
+constraints on the way their are combined, and the semantics of what they
+"mean" at some (possibly more than one) level.  (See also <a
+href="/DesignIssues/Meaning.html">Meaning of web documents</a>)</p>
+
+<p>The test of a good specification is that it clearly defines what
+implementation (document, message, program) conforms, and of course that it
+ensures by its design that whatever conforms works to provides the required
+function.</p>
+
+<h2>The left hand side</h2>
+
+<p>The document should state what sort of things is being defined.  It should
+introduce a new term which characterizes that which conforms to the
+specification. Examples of a conformance term could be</p>
+<ul>
+  <li>A well-formed XML 1.0 document</li>
+  <li>A conforming HTTP 1.1 server</li>
+  <li>An xml-schema-valid XML document</li>
+  <li>A W3C/WAI  "AAA" accessible web site</li>
+  <li>The SVG 1.0 language</li>
+</ul>
+
+<p>The same specification document can define more than one term. such as a
+"strictly conforming WWidget" and a "loosely conforming WWidget" but one
+should beware of diluting the "WWidget" brand.</p>
+
+<p>As systems become more self-describing, the term is given a formal
+identifier. Examples could be</p>
+<ul>
+  <li>The MIME type "image/svg1"</li>
+  <li>The XML Namespace "http://www.w3.org/1999/asdf-2-0"</li>
+</ul>
+
+<p>In this case where a MIME type or namespace has an identifier, then this is
+obviously the crucial term to use to be unambiguous.</p>
+
+<p>Wherever possible, conformance phrases will be grounded in the Web:
+identified by a URI.</p>
+
+<h2>The Right Hand Side</h2>
+
+<p>More has already been written on this, and most of it seems to be in
+consensus in the W3C.</p>
+
+<p>It is important to remember what you are defining as you write the text.
+For example, if you are defining a "foo-valid document" then using "is
+invalid" in the text can be assumed to apply to this but "is incorrect" or "is
+wrong" or "produces an error" does not unless the language is explicitly
+linked to the conformance term.</p>
+
+<p>A good spec similarly pays attention to:</p>
+<ul>
+  <li>The distinction between the use of MUST, as opposed to MAY (etc., see <a
+    href="#Bradner,">Bradner's BCP14</a>)</li>
+  <li>The use of this distinction in defining the conformance term
+  precisely;</li>
+  <li>The distinction between normative and non-normative parts of the
+    specification.</li>
+</ul>
+
+<p>When defining a language, whenever possible specify directly the meaning
+rather than the sort of thing you would expect some software to do with it.
+Typical behaviors of an agent may be very  useful to explain the intent
+non-normatively.</p>
+
+<p>For example,</p>
+
+<blockquote>
+  <p>"x" indicated that the check is void</p>
+</blockquote>
+
+<p>is better than</p>
+
+<blockquote>
+  <p>"x" indicates that the check should be rejected with a fatal error.</p>
+</blockquote>
+
+<p>You can tell people what something means, you can't tell them what to do
+about it, unless you are defining a protocol. When defining a protocol, then
+the constraints should ideally be given as a state transition diagram or table
+to make them totally clear.</p>
+
+<p>When defining a message which in fact binds to human social entities, then
+this must be clear.  You could end up in court explaining it if not.  ("The
+MMTP protocol defines the meaning of a message sent by or on behalf of a party
+herein referred to as the "debtor" to a party referred to as the "creditor".
+The creditor is identified by the foo-email-address...)</p>
+
+<p>When defining a part of a specification deliberately to be similar to
+another specification,</p>
+<ul>
+  <li>Make it clear that you have noticed the similarity;</li>
+  <li>Make it clear whether the similarity is exact and if not where not (and
+    why not);</li>
+  <li>Ideally, it clear that the existing specification is being referred to
+    normatively and is definitive, and that what is in this specification is a
+    non-normative copy for information only.</li>
+  <li>Make it clear whether the use in this specification will track any new
+    version of the referenced specification.</li>
+  <li>Think about whether there is any way in which such changes could break
+    this system.</li>
+  <li>If necessary negotiate constraints with the authority for changes to the
+    referenced specification.</li>
+</ul>
+
+<h2>Test questions</h2>
+
+<p>A few examples of things to ask about a spec -- though generalization is
+difficult.</p>
+<ul>
+  <li>Does the spec give enough information to determine, for any arbitrary
+    object,  whether  the conformance term applies to it?</li>
+  <li>Could you write a program to test conformance?</li>
+  <li>Is conformance alone enough to ensure that systems build using this
+    language will function as intended and with integrity?</li>
+  <li>Can you prove important properties of the system from the state
+    transition tables etc?</li>
+</ul>
+
+<p>So much for another bit of folklore. Comments, suggestions welcome.</p>
+
+<p></p>
+<address>
+  <a href="/People/Berners-Lee">Tim BL</a> 
+</address>
+
+<p></p>
+
+<h3>References</h3>
+
+<p><a href="ftp://ftp.isi.edu/in-notes/bcp/bcp14.txt" name="Bradner,">S.
+Bradner, "Key words for use in RFCs to Indicate Requirement Levels",
+BCP0041</a></p>
+
+<p></p>
+<hr>
+
+
+<p><em>These are some of the raw bits of standards which I picked up from
+Peggie Rimmer at CERN, and from working with IEEE, IETF and W3C specifications
+over the years.  I am sure others have written books on it. Comments,
+suggestions welcome</em></p>
+
+<p><small>Last change $Id: blank.html,v 1.1 1999/05/24 14:24:19 timbl Exp
+$</small></p>
+<address>
+  <a href="/People/Berners-Lee">Tim BL</a> 
+</address>
+</body>
+</html>

+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
+                      "http://www.w3.org/TR/REC-html40/loose.dtd">
+<html>
+<head>
+  <title>The essentials of a specification - Tim BL</title>
+  <link rel="stylesheet" href="/StyleSheets/base.css">
+  <!-- Changed by: tbl 19990524 -->
+</head>
+
+<body lang="en">
+<p><a href="../"><img alt="W3" border="0" src="/Icons/WWW/w3c_home" width="72"
+height="48"></a></p>
+
+<h1>The essentials of a specification</h1>
+
+<blockquote>
+  <p>This note is a little <em>motherhood and apple pie</em> about how a
+  specification should be couched so as to clearly add a new well-defined
+  piece to the technology.</p>
+</blockquote>
+
+<p>A technical specification defines something.  The document must  specify
+the thing being defined as well as give its definition: a "left hand side" as
+well as a "right hand side".  Both must be done quite precisely.</p>
+
+<p>Typically, technical specifications for the web specify a language  or a
+protocol.  A protocol is a language for messages, plus a set of constraints on
+the sequence of messages. A language is a set of symbols, the syntactic
+constraints on the way their are combined, and the semantics of what they
+"mean" at some (possibly more than one) level.  (See also <a
+href="/DesignIssues/Meaning.html">Meaning of web documents</a>)</p>
+
+<p>The test of a good specification is that it clearly defines what
+implementation (document, message, program) conforms, and of course that it
+ensures by its design that whatever conforms works to provides the required
+function.</p>
+
+<h2>The left hand side</h2>
+
+<p>The document should state what sort of things is being defined.  It should
+introduce a new term which characterizes that which conforms to the
+specification. Examples of a conformance term could be</p>
+<ul>
+  <li>A well-formed XML 1.0 document</li>
+  <li>A conforming HTTP 1.1 server</li>
+  <li>An xml-schema-valid XML document</li>
+  <li>A W3C/WAI  "AAA" accessible web site</li>
+  <li>The SVG 1.0 language</li>
+</ul>
+
+<p>The same specification document can define more than one term. such as a
+"strictly conforming WWidget" and a "loosely conforming WWidget" but one
+should beware of diluting the "WWidget" brand.</p>
+
+<p>As systems become more self-describing, the term is given a formal
+identifier. Examples could be</p>
+<ul>
+  <li>The MIME type "image/svg1"</li>
+  <li>The XML Namespace "http://www.w3.org/1999/asdf-2-0"</li>
+</ul>
+
+<p>In this case where a MIME type or namespace has an identifier, then this is
+obviously the crucial term to use to be unambiguous.</p>
+
+<p>Wherever possible, conformance phrases will be grounded in the Web:
+identified by a URI.</p>
+
+<h2>The Right Hand Side</h2>
+
+<p>More has already been written on this, and most of it seems to be in
+consensus in the W3C.</p>
+
+<p>It is important to remember what you are defining as you write the text.
+For example, if you are defining a "foo-valid document" then using "is
+invalid" in the text can be assumed to apply to this but "is incorrect" or "is
+wrong" or "produces an error" does not unless the language is explicitly
+linked to the conformance term.</p>
+
+<p>A good spec similarly pays attention to:</p>
+<ul>
+  <li>The distinction between the use of MUST, as opposed to MAY (etc., see <a
+    href="#Bradner,">Bradner's BCP14</a>)</li>
+  <li>The use of this distinction in defining the conformance term
+  precisely;</li>
+  <li>The distinction between normative and non-normative parts of the
+    specification.</li>
+</ul>
+
+<p>When defining a language, whenever possible specify directly the meaning
+rather than the sort of thing you would expect some software to do with it.
+Typical behaviors of an agent may be very  useful to explain the intent
+non-normatively.</p>
+
+<p>For example,</p>
+
+<blockquote>
+  <p>"x" indicated that the check is void</p>
+</blockquote>
+
+<p>is better than</p>
+
+<blockquote>
+  <p>"x" indicates that the check should be rejected with a fatal error.</p>
+</blockquote>
+
+<p>You can tell people what something means, you can't tell them what to do
+about it, unless you are defining a protocol. When defining a protocol, then
+the constraints should ideally be given as a state transition diagram or table
+to make them totally clear.</p>
+
+<p>When defining a message which in fact binds to human social entities, then
+this must be clear.  You could end up in court explaining it if not.  ("The
+MMTP protocol defines the meaning of a message sent by or on behalf of a party
+herein referred to as the "debtor" to a party referred to as the "creditor".
+The creditor is identified by the foo-email-address...)</p>
+
+<p>When defining a part of a specification deliberately to be similar to
+another specification,</p>
+<ul>
+  <li>Make it clear that you have noticed the similarity;</li>
+  <li>Make it clear whether the similarity is exact and if not where not (and
+    why not);</li>
+  <li>Ideally, it clear that the existing specification is being referred to
+    normatively and is definitive, and that what is in this specification is a
+    non-normative copy for information only.</li>
+  <li>Make it clear whether the use in this specification will track any new
+    version of the referenced specification.</li>
+  <li>Think about whether there is any way in which such changes could break
+    this system.</li>
+  <li>If necessary negotiate constraints with the authority for changes to the
+    referenced specification.</li>
+</ul>
+
+<h2>Test questions</h2>
+
+<p>A few examples of things to ask about a spec -- though generalization is
+difficult.</p>
+<ul>
+  <li>Does the spec give enough information to determine, for any arbitrary
+    object,  whether  the conformance term applies to it?</li>
+  <li>Could you write a program to test conformance?</li>
+  <li>Is conformance alone enough to ensure that systems build using this
+    language will function as intended and with integrity?</li>
+  <li>Can you prove important properties of the system from the state
+    transition tables etc?</li>
+</ul>
+
+<p>So much for another bit of folklore. Comments, suggestions welcome.</p>
+
+<p></p>
+<address>
+  <a href="/People/Berners-Lee">Tim BL</a> 
+</address>
+
+<p></p>
+
+<h3>References</h3>
+
+<p><a href="ftp://ftp.isi.edu/in-notes/bcp/bcp14.txt" name="Bradner,">S.
+Bradner, "Key words for use in RFCs to Indicate Requirement Levels",
+BCP0041</a></p>
+
+<p></p>
+<hr>
+
+
+<p><em>These are some of the raw bits of standards which I picked up from
+Peggie Rimmer at CERN, and from working with IEEE, IETF and W3C specifications
+over the years.  I am sure others have written books on it. Comments,
+suggestions welcome</em></p>
+
+<p><small>Last change $Id: blank.html,v 1.1 1999/05/24 14:24:19 timbl Exp
+$</small></p>
+<address>
+  <a href="/People/Berners-Lee">Tim BL</a> 
+</address>
+</body>
+</html>

+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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+            <div class="w3c_leftCol"><h2 class="offscreen">Site Navigation</h2>
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+  <title>World Wide Web Consortium Clears Patent Hurdle for Web Privacy</title>
+</head>
+
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+<p><a href="../../ "><img src="../../Icons/WWW/w3c_home" alt="W3C"
+border="0"></a></p>
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+
+<h1>World Wide Web Consortium Clears Patent Hurdle for Web Privacy</h1>
+
+<h2>Patent analysis confirms Platform for Privacy Preferences (P3P) does not
+infringe Intermind Patent</h2>
+
+<p><strong>W3C Contacts</strong></p>
+<dl>
+  <dt><strong>USA, Asia</strong></dt>
+    <dd>Janet Daly, &lt;<a href="mailto:janet@w3.org">janet@w3.org</a>>,
+      +1.617.253.5884</dd>
+  <dt><strong>Europe</strong></dt>
+  <dd>Andrew Lloyd, &lt;<a href="mailto:allo@ala.com">allo@ala.com</a>>,
+      +44 1 27 367 5100</dd>
+</dl>
+<hr>
+
+
+<p><a href="http://www.w3.org/">http://www.w3.org/</a> -- 28 October 1999 --
+Removing a major hurdle to the deployment of privacy-enhancing technology on
+the Web, the World Wide Web Consortium (W3C) released a legal analysis finding that
+<a href="../../P3P/">Platform for Privacy Preferences (P3P)</a> technology does not infringe a patent
+held by the Intermind Corporation. P3P enables Web sites to inform users of
+their privacy practices and will give users more control over the use of their
+personal information on the Web.  Widespread deployment of P3P-compliant
+technologies was threatened when the patent holder sought to charge royalties
+for products or services using the P3P specification, despite the fact that
+the technology was developed in an open, collaborative process by a number of
+W3C Members.</p>
+
+<p>"Given the fundamental importance of privacy protection on the Web, and our
+commitment to open standards, we decided that it was our responsibility to
+provide the community with a thorough analysis of the relationship between the
+patent and P3P," said Daniel J. Weitzner, <a href="../../TandS/">Technology and Society</a> Domain Leader at the World Wide Web Consortium, responsible for P3P development.</p>
+
+<p>The complete analysis is available on the W3C Web site at <a
+href="http://www.w3.org/TR/P3P-analysis">http://www.w3.org/TR/P3P-analysis</a>.</p>
+
+<h2>The Analysis</h2>
+
+<p>The Intermind Patent (U.S Patent No. 5,862,325) claims rights in certain
+techniques of controlling interactions between clients and servers, especially
+with respect to the exchange of personal information.  Though much of the
+Internet is based on such technologies, the assertion of proprietary rights in
+this field had a chilling effect on the Web community's plans for P3P
+deployment.</p>
+
+<p>W3C retained noted patent attorney Barry Rein, of Pennie &amp; Edmonds, to
+evaluate the degree to which P3P does or does not infringe the Intermind
+patent. Mr. Rein and his team, assisted by Joseph Reagle, W3C Policy Analyst 
+instrumental in the development of the P3P specification, concluded
+that compliance with the P3P standard can be accomplished without infringing
+Intermind's patent.</p>
+
+<h2>The Legal Argument</h2>
+
+<p>The legal conclusion that P3P technologies would not infringe the Intermind
+Patent rests on a comparison of the technologies claimed in the patent against
+the structure of P3P.  The essential technology in Intermind's patent consists of 
+"communications objects" used as "control structures" to direct
+client-server interactions.  These control structures use object-oriented
+programming techniques to transfer both executable program instructions and
+associated metadata from client to server.  P3P does not infringe the
+Intermind patent because it specifies no such control structure. The analysis
+prepared by Mr. Rein and his team finds:</p>
+
+<blockquote>
+  <p>.... P3P does not include the control structure of the '325 patent claims
+  for at least two fundamental reasons: (1) neither the proposal nor the User
+  Preferences file includes data, metadata, and instructions organized using
+  object-oriented programming to encapsulate the data together with the
+  instructions for using it, and (2) neither the proposal nor the User
+  Preferences file provides location transparency or completely specifies a
+  communications relationship. For these reasons, P3P-compliant Web services
+  and user agents do not literally infringe any claim of the '325 patent.</p>
+</blockquote>
+
+<h2>Web Community Support Critical in Patent Analysis</h2>
+
+<p>During the course of the review, W3C called on the Web community to
+contribute information that might assist the attorneys in their work. W3C 
+received over 100 substantial technology contributions from technologists all
+over the world. W3C would like to thank all who contributed to the effort 
+for their help.</p>
+
+
+<h2>The Importance of P3P</h2>
+
+<p>P3P's design keeps users informed of a Web site's privacy practices, and allows
+users to control what information they choose to disclose to a Web site, as
+well as how that information may be used. P3P privacy disclosures and requests
+for information are expressed in the W3C's widely deployed Extensible Markup
+Language (<a href="http://www.w3.org/XML/">XML</a>).</p>
+
+<p>P3P technology was created by a consensus process involving representatives
+from more than a dozen W3C Member organizations, as well as invited privacy
+experts from around the world.</p>
+
+<p>For the first time in the history of the World Wide Web Consortium, the
+open technology development process came into conflict with intellectual property
+claims. "We felt that we owed it to the Web community to clear up the
+confusion over the Intermind patent," said Weitzner, "but hope not to make
+this a regular practice."</p>
+
+<h2>About the World Wide Web Consortium (W3C)</h2>
+
+<p>The W3C was created to lead the Web to its full potential by developing
+common protocols that promote its evolution and ensure its interoperability.
+It is an international industry consortium jointly run by the <a
+href="http://www.lcs.mit.edu/">MIT Laboratory for Computer Science (MIT
+LCS)</a> in the USA, the <a href="http://www.inria.fr/">National Institute for
+Research in Computer Science and Control (INRIA)</a> in France and <a
+href="http://www.keio.ac.jp/">Keio University</a> in Japan. Services provided
+by the Consortium include: a repository of information about the World Wide
+Web for developers and users, reference code implementations to embody and
+promote standards, and various prototype and sample applications to
+demonstrate use of new technology. To date, over 350 organizations are <a
+href="/Consortium/Member/List">Members of the Consortium</a>.</p>
+
+<p></p>
+<hr>
+
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