Antville for social microblogging.

Mastodon is a free, open-source social network server. A decentralized alternative to commercial platforms, it avoids the risks of a single company monopolizing your communication. Anyone can run Mastodon and participate in the social network seamlessly.

It already looks like Tweetdeck from the start and of course, you might guessed it, you can find me there as the usual suspect @p3k.

Relevant: The free and open social web.