When Twitter put out its strict new API guidelines, there was some doubt as to whether or not third-party clients like Tapbots' Tweetbot for Mac would even make the cut -- the user caps and other curbs on unofficial apps potentially made it tough to develop competition around a different (and possibly better) experience. That makes today's official appearance of Tweetbot in the Mac App Store as much symbolic as it is practical. While there won't be many significant shocks for those who've been participating in Tweetbot's alpha and beta stages,
