TweetDeck by Twitter
Mac OS Social Networking
TweetDeck makes it easier for publishers, marketers and power users to track the real-time conversations they care about. It brings more flexibility and insight to power users through a customizable layout that lets you keep up with the people and topics that matter most to you. And, you can join the conversation by tweeting, sharing photos and links to news stories, and more.
Enhancements and small bug fixes.