In the spirit of introducing at least one new syndication format every day, we at The RSS Blog have decided to release our own version, as promised, of RSS. Introducing RSS 4.0. The spec for RSS 4.0 can be found here. This new format deprecates all RSS 0.9x, RSS 1.1, RSS 3.0 and the other RSS 3.0. Producers of RSS 0.9x, 1.1 and 3.0 must immediately upgrade as their format is here-forth considered obsolete.
So true. At last count, we have RSS 0.9, 0.91 (Netscape), 0.91 (Userland), 0.92, 0.93, 0.94 (kinda), 1.0, 1.1, 2.0, 2.01, 2.01 revision 2 (spec update without version bump), 3.0 and another 3.0. None of these 13 specifications are developed through standards bodies and some are just written for kicks and manage to get published on Slashdot anyway.
Rock on Atom 1.0.