Similar instance here -
Except with the instant messaging system. I've been invited to a number of sessions where someone inadvertently hit the "active users" list prior to clicking "Send invite." As our users are scattered across the globe, it got interesting quickly as weather reports and greetings to old colleagues were sent about. These tended to run about 10-15 minutes as the traffic would swell, spike, and decline.
Unfortunately, our system doesn't support any sort of pictures or it wold have gotten right out of hand.