If I were betting, I'd bet many of the supposed bugs are readers working around incorrectly-implemented servers. If the feed doesn't update, but it's because o

If I were betting, I'd bet many of the supposed bugs are readers working around incorrectly-implemented servers. If the feed doesn't update, but it's because of a server bug, your users are still left unhappy. In a perfect world the readers would note which servers are implemented correctly and which you can't trust last-updated / etags etc... that's a lot of work.