If you're using IM clients on the job and would rather it remained unknown...

Stick to MSN Web Messenger. Yes, Emessenger is better, it doesn't reload your conversation everytime you send a message, it allows nudges, it lets you put a picture up and all that but everytime someone new IM's you, the conversation window pops up on your screen... which might cause you a fair amount of stress when that happens when somebody else happens to be in your office. Web Messenger doesn't do that. The window calmly remains in the background until you decide you wanna look at it. This is priceless, people. Believe me.