I'd just as soon block all instant messaging. Completely. In the few cases where it is for business intents, we'll use a service like SameTime. I've seen viruses, child pornography and the likes hit a company network because of instant messaging. It isn't a matter of "it's my network, all mine", it's a matter of liability and responsibility.
I, to this day, have not found a viable solution to blocking Instant messaging, without blocking all of yahoo, all of msn, all of aol, etc. Tim
