Windows/Mac/Linux (Adobe Air): Social media organiser TweetDeck pares down configuration buttons, adds full Facebook feeds and new MySpace support, and integrates more tightly with link shortening service Bitly in a new version. In other words, it's worth the update.
TweetDeck is mainly a Twitter client, but it's been making inroads into helping you organise, search, and compress your other social networks in later versions. Adding columns is now a bit more intuitive and specific, as TweetDeck asks you which account the column should come from, and which aspects of a feed should be shown. Along with the aforementioned status-checking features, there's now drag-and-drop photo uploading for Facebook posting, and new lists of recommended Twitter accounts to follow for different types, like "Journalists."
TweetDeck is a free download, works anywhere the Adobe AIR platform does.