Because there are different versions of RSS, the term RSS is most frequently used as a name to mean the syndication of Web content, rather than as an acronym for its founding technology. When using the name RSS the speaker may be referring to any of the following versions of Web content syndication:
- RDF Site Summary (RSS 0.9, RSS 1.0)
- Rich Site Summary (RSS 0.91, RSS 1.0)
- Really Simple Syndication (RSS 2.0)
When using the term RSS, most will use it in reference to Rich Site Summary or the previous version called RDF Site Summary. When referring to Really Simple Syndication, it will usually be called RSS 2.0, not RSS. There are several versions of RSS available, with the most commonly implemented version being RSS 0.91. The most current version, however, is RSS 2.0 and it is backward-compatible with RSS 0.91. RSS was originally developed by Netscape. The RSS 2.0 specification was authored by Dave Winer.
Compare with Atom, an alternative open source XML-based Web content and metadata syndication format.