I use it all the time, usually have at least 3 conversations going on and I do keep in touch with people on my list, a 'hi' and 'hello' and then a convo from there :V
I'm on it all the time as it's my main way to get in contact with my boyfriend. However, unless someone else is steering the direction(besides with him), I tend to be rather quiet. Thus I don't really use any of my own 'public' IM services anymore.
Devious Comments
(oh god, the Microsoft-enabled puns, someone shoot me)
Took me a couple seconds, lol.
I used many chatting s/w before, YM!, AIM, skype, gtalk, msn. but i like msn most