An unhappy discovery about feeds in Leopard.
At Linden Lab we use an internal wiki, and I wanted to subscribe to the recent changes feed in Mail.app. The wiki uses HTTP authentication. When I tried updating the feed after I added it, instead of asking for my credentials, Mail threw an error dialog reporting that the feed was password protected, but didn’t ask for the credentials.

2 Comments
I think Safari’s web clips have this problem too. I wanted to clip an internal Wiki page from work (which uses HTTP auth), and it clipped it, but when I re-launched dashboard, it just said it couldn’t load the page.
Pretty weaksauce, IMO.
Here’s the unsatisfying work-around I found for this problem.
http://discussions.apple.com/thread.jspa?threadID=1231211