I use instant messaging for work. I work for a big company with offices all over the planet. We use Sametime, which is ok but not very fancy compared to the MSN/Yahoo/AIM.
There are some nice things about it though. It is secure. I know I'm chatting with who I think I'm chatting with, because you sign on with your Lotus Notes name and password. You can't pretend to be Bill Gates or whoever. <img src=icon_smile_big.gif border=0 align=middle>
It also has some nice things for holding online meetings with groups of people, with tools for electronic whiteboard and application sharing.
It offers audio and video, which I've played around with a little but doesn't seem to add much value. Mostly if I really need to talk to someone, I'll IM them (since I know they're online), then call them.
It's useful because it's quick, easy and cheap. You can multi-task, carrying on a discussion with someone on a part-time basis while you're on the phone or going through email.
I wish there was a way to search for people with a certain interest (like Odigo's people-finder) and then broadcast an IM to them. Sometimes it's hard to find someone with specialized expertise in a company as big as ours, and that would make it much easier. You can with Sametime send chat requests to a predefined group list, but you have no control over who is in the list.
IM makes work move along much more smoothly and helps fill in the communication gaps that used to exist (phone tag, geographic boundaries, etc.).
Gandalf
=== Absolute power corrupts absolutely ===