I don’t use any messengers at work: MSN, Yahoo, AOL, whatever. 😉 But that makes me sound like a caveman, so I don’t broadcast that fact.
I used to have a peer in another workplace who used to send me orders through messenger (“Would you please fix the issue on…”) It was easier to uninstall messenger than to have the whole conversation about how I didn’t work for him. I never really missed it, although I admit on occasion it is a really wonderful tool.
If I land on a team that really uses a messenger as a communication tool, I can pick it back up. But right now I enjoy the Neolithic quiet.