Yea the feeds sort of broken. The new system (Drupal 4.5) doesn't have native support for Atom, RSS1 and RSS2 feeds yet. I had to find a third party module to support RSS1/RSS2/Atom feeds.

I tweaked the feeds a little more today. In particular the multiple items coming up if you're using RSS2 has been fixed. Items would come up multiple times if they were filed into multiple categories. I removed the categories tag out of the RSS2 feed and that fixed the problem.

For the best experience I would recommend using the RSS 0.92 feed since it provides the best data because it is part of drupal core.

Please share your comments. Thanks.