No groups on Mac Twitter apps?
"Tweetie, if you add groups right now, you will destroy TweetDeck. This is your window of opportunity. Make it happen" (Taken from a blog post by @cksample)
I don't understand why the Mac native Twitter app devs seem to have such an aversion to adding groups. So Twitter doesn't support it. Wahhh.
Tweetie has already destroyed TweetDeck in the future. It just hasn't happened yet.
Groups are one of those features that are demanded by high-needs web celebrities and completely unnecessary to 95% of users … and Tweetdeck was designed to appeal to those people. Tweetie will never "beat" Tweetdeck for that audience. Different design priorities.