We are using a lot ComAgent IM internaly, and sometimes users have to create a group discussion (with many people or everyone) to get an information. Sometimes, it turn in jokes exchange and some other people want to be able to stop receiving this group discussion. If you close the window, the next time someone post to this discussion you keep getting the message.
It would be nice to be able to QUIT the discussion.
And on the other side it would be nice that the initiator of the discussion keep able to reinvite someone to the current discussion.