AtomSyntax is a blog syndication and API standard and competes with RssFeeds. The standard took form on the Pie wiki, http://intertwingly.net/wiki/pie/FrontPage.
TimBray? wrote to IETF, in 2004, that the work is finishing and should consider winding down. See http://www.tbray.org/ongoing/When/200x/2004/11/11/AtomInnovation
Most current draft is at http://www.ietf.org/internet-drafts/draft-ietf-atompub-format-11.txt
To be exact, the standard hasn't yet taken form, and not all the work is being done on the wiki itself. It would appear that they often use mailing lists ( http://www.imc.org/atom-syntax/index.html) to have chatty discussions, and then focus the wiki work on writing authoritative documents. An interesting model to consider.
Some thinks the AtomSyntax is reducing the momentum of RssFeeds. See http://www.internetnews.com/ec-news/print.php/3334651.
Resources
May05 intro by author Danny Ayers at http://www.newssummit.org/2005/presentations/RSSandAtom.pdf