Word is that Twitter made the call today: Twitter for Mac is done. They won’t kill it outright, but no further updates. Goodbye, old friend.
I was using the Twitter for Mac client when it was Tweetie for Mac, and haven’t found it the same since.
It’s pretty obvious they didn’t want it, and only bought it because it was part of the package that came along with the iPhone and iPad clients.
It’s last update was in June 2011, and those were just minor bug fixes..
Obviously, it’s dead. The difference now is that Twitter won’t let anyone else replace it, probably because they can make far more money by making people use their website.