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2005-08-12
XPath & XQuery
XPath & XQuery

Newsletter Discussion

Abstract

RSS and Atom are the new ways for providing updates for news feeds. This newsletter gives an overview of RSS & Atom and lists an RSS version summary and its compatibility issues.

RSS & Atom News feed

What is RSS?

RSS provides a news update from a website in simple form such as a file for computer. These simple files can be read by an aggregator, which collects news from various websites and provides them collected to the user. RSS was developed by various groups, which led to various versions of RSS available today.

Different Versions of RSS:

The first version, RSS 0.90 known as Rich Site Summary was developed by Netscape. It is based on XML format. It was deemed as overly complex for its goals. So a simpler version 0.91 was proposed.
0.91 was picked up by another vendor, UserLand software from Netscape for further development. They continued to evolve the 0.9x branch through 0.92, 0.93, 0.94 and finally 2.0.
Another non commercial group developed a new format based on the original 0.90 version of Netscape. This format RSS 1.0, known as RDF Site Summary was perceived on the guidelines of W3C's Resource Description Framework (RDF). By leveraging RDF, RSS 1.0 streams can take part in the Semantic Web.
The latest version of RSS 2.x is also known as Really Simple Syndication. RSS 2.0.1 like the 1.0 format is considered frozen, and allows for extensibility through modules living in their own namespaces.

Recommendation for usage of RSS versions:

Following are the recommendations of using various versions of RSS given at http://www.xml.com/pub/a/2002/12/18/dive-into-xml.html.

RSS Version	Recommendation
0.90	Obsolete
0.91	Simple. Use for basic syndication. Provides easy migration path to 2.0 if you need more flexibility.
0.92, 0.93, 0.94	Use 2.0 instead
1.0	Use for RDF based application or when you need advanced RDF specific modules.
2.0, 2.0.1	Use for general purpose. Provides metadata rich syndication.

Compatibility:

Most of the RSS readers (aggregators) are able to understand various RSS versions. Though RSS 1.0 and RSS 2.x allow a lot of metadata to be encoded, most of the aggregators present today can read only the basic metadata fields.

Atoms:

To avoid the confusion of various RSS formats and their incompatibility Atom standard was created. Atom is a XML-based document format designed for the syndication of Web content. It is based on experience gained in using various versions of RSS. Atom is working in progress within IETF. The latest version available is Atom 0.3. At present it is generated by various Google related services such as "Gmail" and "Blogger". The Atom Syndication Format is being developed as the replacement of RSS.