The new TweetDeck. (Credit: Screenshot by Seth Rosenblatt/CNET)

The new TweetDeck (download for Windows and Mac) has launched, and it's the first version since Twitter bought the company. There's a new logo and blue skin to reflect that, but far bigger changes happened under the hood.

It's not entirely clear when the new versions were released, since Twitter didn't announce them, but the company has completely abandoned the old program. Gone is the cross-platform program built on Adobe AIR, and gone are many of its features. In its place, Twitter has built two new programs native to Windows and Mac, respectively, and streamlined their functionality to more closely reflect the official Twitter workflow. TweetDeck is still available as a Chrome Web App, and for iOS and Android, although they haven't recent an upgrade like the Windows and Mac clients.

Before its purchase, TweetDeck had released native clients alongside the AIR version, but the new releases appear unrelated.

The basics of TweetDeck's functions remain, including multiple Twitter and Facebook account support and customizable columns, while new-Twitter style retweeting and direct messaging have been improved. There's also separate columns for Facebook newsfeeds and Facebook notifications.

Old TweetDeck users can log in with their TweetDeck accounts to save the trouble of re-entering in multiple account usernames and passwords.

Facebook is now the only non-Twitter account that TweetDeck supports. MySpace, LinkedIn, Foursquare, and Google Buzz have all been dropped. The loss of Buzz is not exactly catastrophic, but it does indicate that Twitter isn't about to drop its hard line on cross-social network pollination. Also gone are color and font customizations, keyboard shortcuts, URL shortening service options, and TweetDeck's tweaks to minimize API calls.

Notification box moving still exists, but now you simply grab it when it appears and drag it to the part of the screen you want it to be in. That's a definite improvement over the weird X-Y axis widget in the old TweetDeck's settings.

Overall, I found the new TweetDeck experience to be better than the old one. There's less behavioral wonkiness, and it feels like it's natural extension of Twitter. However, dropping support for all accounts besides Twitter and Facebook doesn't bode well for people who have their hopes up for Google Plus integration.