Then I started trying out http://www.posterous.com which takes anything I email them (like this), throws it on a blog and then updates twitter. That and a couple of people who've sent me actual tweets (ok, that still sounds silly) and the service just comes alive.
And the reasons I prefer it over normal IM – well mainly because of the whole "who's online" thing – I hate being pinged in IM by people at random times – if maybe I just logged on to check one thing in google, or I'm trying to write some code or play a game. So what do I do, well I shut down the IM client – or even worse make sure it doesn't start at startup. And from there on in it becomes pointless.
With Twitter there is no concept of being online – you just post anytime you want – and read others posts anytime you want. You can keep track of those sent to your ears, as well as what the world is saying (I think Search was the big thing missing, but now they've got that sorted too).
And if you close your twitter client (or heaven forbid twitter is down) then that's just a while for you to get more work done :)