Despite what Twitter has announced, the folks at Tapbots are marching on with Tweetbot for Mac. The release of alpha 3 today adds the ability to split columns into their own windows which are dockable to create a multicolumn interface. This puts the app in direct competition with Twitter’s own TweetDeck in addition to the long-neglected Twitter for Mac. While this is perhaps the best Twitter app yet, you can sort of imagine Twitter’s executives sharpening their knives ready to cut access to its API from developers like Tapbots. The app can be downloaded for free here.