What is RSS?

RSS is a format for syndicating news and content of news-like sites, including major news sites like Wired, news-oriented community sites that Slashdot and personal blogs. But it is not just for news. Generally speaking, everything that can be split into separate items can be syndicated via RSS: "recent changes" page of a wiki, a ChangeLog of CVS checkin, even the revision history in a book. When information on each item is in RSS format, an RSS-aware program can check the feed for changes and react to changes in an appropriate manner.

RSS-aware program called news aggregators are popular in the weblogging community. Many weblogs make content available in RSS. A news aggregator can help you keep up with all of your favorite blogs by checking their RSS feeds and display the new items from each of them.

A brief history of RSS
But coders beware. The name "RSS" is an umbrella term for a style that cut across several different versions of at least two different (but in parallel) format. The original RSS, version 0.90, was designed by Netscape as a format for building portals of headlines to the traditional news sites. It was considered too complex for their targets, a simpler version, 0.91, was proposed and subsequently dropped when Netscape lost interest in the portal-making business. But 0.91 was picked up by another supplier, Userland Software, which is intended to be used as a basis for its weblogging products and other web-based writing software.

In the meantime, a third, non-commercial group split off and designed a new format based on what they perceived as the original guiding principles of RSS 0.90 (before it got simplified 0.91). This format, which is based on RDF, known as RSS 1.0. But Userland was not involved in designing this new format, and, as an advocate of simplifying 0.90, it was not happy when RSS 1.0 was announced. Instead of accepting RSS 1.0, Userland continued to develop the 0.9x branch, by versions 0.92, 0.93, 0.94, and finally 2.0.