Although it's still awaiting the final go-ahead, Atom 1.0 is essentially ready. The Atom Syndication Format, to give its full name, is essentially a competitor to RSS 2.0, but developed by a larger working group and with more rigid definitions of what each element can do. It's also in the process of becoming an official standard as approved by the IETF, whereas RSS has not yet been approved by any standards body (AFAIK). In addition, it supports things like encryption and a greater depth of metadata.
I imagine that MT 3.2 will support this new version upon final release (to quote Anil: We'll be announcing more details of our coming support for the Atom 1.0 format shortly
) and presumably its other backers such as Google will also adopt it soon.
I'm also wondering whether to move all of my feeds to Atom, now that it's (nearly) a proper standard. Offering two sets of feeds is confusing and so just sticking with one should make subscription easier. The essential makeup of an Atom feed has not changed hugely since 0.3 when the format became quite widely adopted and most aggregators support it natively.
Update: A comparison between RSS and Atom. It's written by Tim Bray who is part of the Atom working group, so it's likely to be biased towards Atom, but still interesting.
I have Atom 0.9.2 and FeedBurner RSS 2 on my site.
Erm, no, you have Atom 0.3 and a Feedburner feed on your site. There is no such standard as Atom 0.9.2, as far as I know.