1. 1 Really Simple Syndication RSS 0.91,RSS 0.92,RSS 2.0 Presented by: Vasudha Bhat Madhukesh Wali

2. 2 Outline  Why so many RSS versions?  The two Contenders  The Events..  XML/RDF…?  The two incompatible versions of RSS 0.91  New elements in RSS 0.91  RSS 0.92 UserLand  RSS 2.0 Specification

3. 3 Why so many RSS versions?  Purpose  Meta data support  Light weight content syndication  Upgrade  Extending features  Competition

4. 4 The two Contenders Dave Winer -XML Based UserLand Vs Ramanathan Guha -RDF Based Netscape / RSS-DEV Working Group

5. 5 The Events..  Userland starts offering ScriptingNews syndicated in XML  Netscape comes out with RSS 0.9 based on RDF  Userland aggregator supports RSS 0.9  Userland releases 2.0b1  Netscape publishes a non RDF format RSS 0.91 with features similar to 2.0b1  AOL acquired Netscape loses interest in the format  Userland releases its version of RSS 0.91 in an effort to support RSS  Userland releases further version RSS 0.92  RSS-DEV Working Group releases RSS 1.0 with support for RDF  Userland releases RSS 2.0 Netscape / RSS-DEV Working GroupUserLand

6. 6 Round 1- Keep it Simple Dave Winer (XML Based) RSS 0.91 Vs Ramanathan Guha (RDF Based) RSS 0.9 Winer wins!!!

7. 7 Round 2 - Meta Data Support UserLand-Winer (XML Based) RSS 2.0 Vs RSS-DEV Working Group-Guha (RDF Based) RSS 1.0 Winer loses!!!

8. 8 XML/RDF…? XML  sufficient for web content syndication  Light Weight, easy, faster deployment  Ex RSS 0.91, RSS 2.0...depends on what you want to do. RDF  Supports Meta data syndication  More effort needed in creating RDF based feeds  Ex. RSS 0.9, RSS 1.0

9. 9 UserLand's version -Dave Winer... 24.. No DTD/named entities exist Netscape's version - Dan Libby... 0.. Supports named entites as defined in the DTD The two incompatible versions of RSS 0.91 Though claimed to be compatible by UserLand, subtle differences exists[1] making the two versions incompatible

10. 10 New elements in RSS 0.91 ICC http://icc-cricket.yahoo.com/ Cricket around the world en-us Copyright 2000, WriteTheWeb team. editor@icc-cricket.yahoo.com webmaster@icc-cricket.yahoo.com Februrary 26, 2008 http://backend.userland.com/rss091 Sunday 12 ICC http://icc-cricket.yahoo.com/images/icc-u19.jpg http://icc-cricket.yahoo.com/news/news.htm 88 31 India advances to finals http://icc-cricket.yahoo.com/2008/feb/news20080224-88.html Sachin Tendulkar posted his first half century of the series and India secured a place in the limited-overs tri-series finals on Tuesday Black existing items Blue new elements Bold –required elements

11. 11 RSS 0.92 UserLand  Upward compatible with RSS 0.91(UserLand)  Every new feature of 0.92 is optional  element optional  All sub elements of item optional  Allowed entity encoded HTML  New sub elements 

12. 12 New elements in RSS 0.92  credit and publicize the sources of news items can be used by aggregators to determine similar updates ICC http://icc-cricket.yahoo.com/ Cricket around the world India advances to finals http://icc-cricket.yahoo.com/2008/feb/news20080224-88.html Sachin Tendulkar posted his first half century of the series and India secured a place in the limited-overs tri-series finals on Tuesday ICCI INDIA/final/scorecard <cloud domain=“icc-cricket.yahoo.com" port="80" path=“/RPC2” registerProcedure=“score.Notify" protocol="xml-rpc"/>   specifies a Web application that supports the rssCloud interface  The subsciber registers to the rssCloud interface specified by the cloud element for notifications  Registration expires every 24 hours  hierarchic location in a category  Attach additional files associated with the item

13. 13 RSS 2.0 Specification  First introduced in August 2002.  A summary of RSS (2.0) version history.  Evolution of 2.0 version  Why RSS 2.0?  Changes and additions in RSS 2.0

14. 14 Evolution of 2.0.1 version  RSS 2.0, which is 0.92 with optional elements, designed by DW, after leaving UserLand.  While in development, this format was called 0.94. - 9/18/02.  RSS 2.0 spec released through Harvard under a Creative Commons license. - 7/15/03.

15. 15 Why RSS 2.0 ?  Backward compatible  Namespaces  Module

16. 16 How is RSS 2.0 different from other versions?  RSS 2.0 is basically RSS 0.92 with modules allowed and a handful of additional elements.  Restricted URI scheme  Prior to RSS 2.0, - http:// and ftp://  RSS 2.0 - http://, https://, news://, mailto: and ftp://

17. 17 Required / Optional Elements  Required channel elements:  title  link  description  RSS Version Comparison http://www.rssdotnet.com/documents/version_comparison.html http://www.rssdotnet.com/documents/version_comparison.html

18. 18 Channel Elements - Comparison CHANNEL.901.0.91.922.0 NNNNO NNNNO NNROO NNOOO NNOOO NNOOO NNOOO R - required O - optional N - not supported

19. 19 Item Elements - Comparison ITEM.901.0.91.922.0 RRROR NOOOO RRROO NNNNO NNNNO NNNNO R - required O - optional N - not supported

20. 20 RSS 2.0 - Added Features  CHANNEL  Generator  ttl  GUID   isPermaLink attribute  ITEM  Example: http://raytheon.cs.odu.edu/hpbc-dad/rsshttp://raytheon.cs.odu.edu/hpbc-dad/rss

21. 21 Rule changes - Generator  Generator :A string indicating the program used to generate the channel. ICC Cricket http://icc-cricket.yahoo.com/ CRICKET AROUND THE WORLD DB ARTISON 90 en-us ICC Cricket http://icc-cricket.yahoo.com/news/2008/february/news20080224- 88.html Fast bowler Brett Lee took five wickets, including three in \ seven balls late in the innings, to help Australia beat Srilanka by 18 runs a free-scoring tri-series ODI on Sunday. Thu, 31 Jan 2008 17:22:01 vbhat@cs.odu.edu http://icc- cricket.yahoo.com/rankings/rankings.html ………

22. 22 Rule changes - guid  guid - globally unique identifier An optional subelement of item that should contain a string that uniquely identifies the item.  isPermalink –true  url that can be opened in a Web browser, that points to the full item described by the element ICC Cricket http://icc-cricket.yahoo.com/ CRICKET AROUND THE WORLD DB ARTISON 90 en-us ICC Cricket http://icc-cricket.yahoo.com/news/2008/february/news20080224- 88.html Fast bowler Brett Lee took five wickets, including three in \ seven balls late in the innings, to help Australia beat Srilanka by 18 runs a free-scoring tri-series ODI on Sunday. Thu, 31 Jan 2008 17:22:01 vbhat@cs.odu.edu http://icc- cricket.yahoo.com/rankings/rankings.html http://icc- cricket.yahoo.com/news/2008/february/news20080224- 88.html

23. 23 ICC Cricket http://icc-cricket.yahoo.com/ CRICKET AROUND THE WORLD 90 en-us ICC Cricket http://icc-cricket.yahoo.com/news/2008/february/news20080224- 88.html Fast bowler Brett Lee took five wickets, including three in \ seven balls late in the innings, to help Australia beat Srilanka by 18 runs a free-scoring tri-series ODI on Sunday. Thu, 31 Jan 2008 17:22:01 vbhat@cs.odu.edu http://icc- cricket.yahoo.com/rankings/rankings.html http://icc- cricket.yahoo.com/news/2008/february/news20080224-88.html Rule changes - Author  Author An optional subelement of item that should contain the email address of the author of the resource referred to within the item.

24. 24 Rule changes Continued.....  ttl An optional subelement of channel that contains a number, which is the number of minutes the reader should wait before refreshing the feed from its source.  pubDate An optional subelement of channel that should contain the publication date for the content in the channel....... ICC Cricket http://icc-cricket.yahoo.com/ CRICKET AROUND THE WORLD 90 en-us ICC Cricket http://icc-cricket.yahoo.com/news/2008/february/news20080224- 88.html Fast bowler Brett Lee took five wickets, including three in \ seven balls late in the innings, to help Australia beat Srilanka by 18 runs a free-scoring tri-series ODI on Sunday. Thu, 31 Jan 2008 17:22:01 vbhat@cs.odu.edu http://icc- cricket.yahoo.com/rankings/rankings.html http://icc- cricket.yahoo.com/news/2008/february/news20080224-88.html

25. 25 Module in RSS 2.0  The first module available for RSS 2.0 was blogChannel created by Dave Winer.  BlogChannel module: Namespace: xmlns:blogChannel=http://backend.userland.com/blogChannelModulehttp://backend.userland.com/blogChannelModule  blogRoll -- the URL of an OPML file containing the blogroll for the site.  mySubscriptions -- the URL of an OPML file containing the author's RSS subscriptions.  blink -- the URL of a weblog that the author of the weblog is promoting.

26. 26 RSS 2.0 an Example Person A A simple example 11 members each that is played on a field having two wickets 22 yards (20 m) apart Person B A simple example Any of several jumping, orthopterous insects of the family Gryllidae, characterized by long antennae

27. 27 RSS 2.0 With Namespaces  In the example it's obvious that his definition of (how the game is played) is different than your definition of (Kind of insect).  How are the readers supposed to know which is being talked about? game or insect?  Namespaces: Namespaces allow you to create any new element you desire, without causing problems with other elements  Simple rule RSS 2.0 - A RSS feed may contain elements not described on this page, only if those elements are defined in a namespace.

28. 28 RSS 2.0 an Example - Namespaces <rss version="2.0" xmlns="http://backend.userland.com/rss2" xmlns:insects="http://www.example.com/insects#" xmlns:games="http://www.foobar.com/ns/games/"> A simple example 11 members each that is played on a field having two wickets 22 yards (20 m) apart Any of several jumping, orthopterous insects of the family Gryllidae, characterized by long antennae

29. 29 RSS 2.0 - Roadmap  RSS is by no means a perfect format, but it is very popular and widely supported.  The RSS spec is, for all practical purposes, frozen at version 2.0.1.  Extended Study - Atom, an XML-based Web content and metadata syndication format.

30. 30 Conclusion  The intense competition have resulted positive outcomes.  We see a lot of incompatibilities between the various versions.

31. 31 VersionOwnerPros Status Recommendation 0.90Netscape ------Obsoleted by 1.0Don't use 0.91UserLandDrop dead simple Officially obsoleted by 2.0, but still quite popular Use for basic syndication.Easy migration path to 2.0 if you need more flexibility 0.92, 0.93, 0.94 UserLandAllows richer metadata than 0.91 Obsoleted by 2.0Use 2.0 instead 1.0RSS-DEV Working Group RDF-based, extensibility via modules Stable core, active module development Use for RDF-based applications 2.0UserLandExtensibility via modules, easy migration path from 0.9x branch Stable core, active module development Use for general- purpose, metadata-rich syndication Version Details:

32. 32 References:  http://diveintomark.org/archives/2004/02/04/incompatible-rss http://diveintomark.org/archives/2004/02/04/incompatible-rss  http://backend.userland.com/rss091 http://backend.userland.com/rss091  http://backend.userland.com/rss092 http://backend.userland.com/rss092  http://cyber.law.harvard.edu/rss/rss.html http://cyber.law.harvard.edu/rss/rss.html  http://cyber.law.harvard.edu/rss/enclosuresAggregators.html http://cyber.law.harvard.edu/rss/enclosuresAggregators.html

33. 33 Questions ????  How are they different? s and s  Which is better XML/RDF?