Well IT blocked our Meebo access so we all have to use the IM client of our choice and allow the company to monitor our conversations. I wouldn't mind BUT they can't get the monitoring right, so it is pretty much up to God's grace to get you logged in.
Googletalk doesn't work
Pidgin doesn't work
I finally gave up and went back to Yahoo Messenger to discover they also blocked our access to messenger.yahoo.com so we couldn't even download the client. I had a buddy outside the wall send it to me. I then had to undock and work, then redock my laptop and...
I can't log in to Yahoo.
So not only have we been effectively blocked from defrauding the company, but we also cannot communicate between ourselves for support. Very effective.