I've been on Twitter for 8 months now, and it's by far my favourite social networking site. It's the pure essence of micro-blogging. I've found that I discover - via succinct, 140-character 'Tweets' - an abundance of interesting posts and tidbits than had I spent 3-4 times more scouring various websites for the same information.
How best, then, to show my appreciation for the site than to create an interpretation of the Twitter bird - in this case, one that would fit comfortably in the Sketchbot universe! I present to you, TweetBot.