2005/07/21: RSS 2.0 is widely deployed and Atom 1.0 only by a few early adopters, see KnownAtomFeeds and KnownAtomConsumers . 2006/01/22: Atom 1.0 in basic form is widely supported. Many aggregators fail on feeds that do not resemble the structure of an RSS 2.0 feed closely. However, several have accepted bug reports, and a few have even released fixes. See ConformanceTests for current status. 2006/05/21: Atom 1.0 is widely supported in major consumer feed-reading applications, the notable exception being Bloglines. 2006/06/20: Bloglines rolled out its new Atom 1.0 parser, so now Atom 1.0 is widely supported in all major consumer feed-reading applications.