Following a request for cooperation with another web site, I've extended my web front end for newsgroups, dev.newswhat.com, with atom feeds. You can now pick a group and (manually for now) enter it in a URL like:
http://dev.newswhat.com/atomthreads.xmldata?group=borland.public.delphi.non-technical
Just change the group name after the = sign and it should work. Notice the the site hosts Delphi groups, many other CodeGear groups (still formally under the "borland" name) plus many Microsoft areas, the public comp.lang forums, and other developers oriented newsgroups. I plan moving the third-party Delphi groups from delphi.newswhat.com soon.
Let me know if the feed works for you and whether you find it useful. Getting a notification that a thread has started without much more info on how it grows seems of limited use to me, but I might be wrong... Global feedback about the dev.newswhat.com site is welcome, as well.