When did Twitter kill instant messaging?

A funny thing happened on the way to the blog this morning. I checked my email, caught up my RSS feeds in Google Reader, and scanned last night’s Twitter activity in TweetDeck (which is so good it’s actually worth installing Adobe Air, thanks Alli). And I realized I didn’t have Google Reader or Live Messenger open. That I haven’t had them open for some time now. And that I don’t really use them anymore. Everyone I talk to on a regular basis is on Twitter.

This may be not restricted to Twitter and more a function of social networks in general, but I’m far more active on Twitter than I am on Facebook, MySpace or LinkedIn (though I’m trying to grok Facebook). But I’ve noticed that since I started using Twitter and following everyone I know or am interested in, my instant messaging use has dropped through the floor and even my text message use has dropped off sharply. If I want to get someone’s attention and it’s not worth an email, I’ll tweet. If it’s private, I’ll send a Twitter Direct Message. I’ve got twitter clients on all my computers, including my smartphone (TweekDeck on desktop and netbook, Tiny Twitter on the Touch Pro, though I tend to waffle between TT and ceTwit and PockeTwit), and even use the Twitter web site when I’m at the office behind our proxy. It’s become my preferred method for light not-in-person (out-person?) conversation.

Do you tweet? And if so, has it replaced IM for you?