There are times when you get blasted with many IM messages at one time. If I could see that someone already had an IM session open, I would not IM them and hope others would do the same or at least know you are one of many IMs the person has going. If you could see perhaps with a number next to the name indicating how many current sessions are in progress, it would cut back on IMs that can wait or be sent with email.
Idea No. 551