Well, I am looking at the registry. Right now in IE7 the feed finder will only find RSS. To add more types, goto
HKEY_LOCAL_MACHINESoftwareMicrosoftInternet ExplorerFeed Discovery
you can add other types there
like application/atom+xml
Close all IE windows, and then goto a site with an atom feed. The feed discovery button will light up!
Steve Novoselac's Blog 
One reply on “Hacking IE7 Feed Discovery – More than RSS!”
Nice find 🙂
Unfortunately, since IE 7 Beta 1 doesn’t support Atom in its feed viewer yet, you won’t get the nice view of the feed you’ll get for RSS 1.0 and 2.0 feeds.
– Sean Lyndersay
http://blogs.msdn.com/rssteam
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