Why would someone operate more than one guest in a chat room?

I am not too familiar with chat rooms, but I thought I would try to join the action on Ziggy TV. If you run your cursor over the avatars of the users a profile pic will pop up if they have one. Well I noticed that there were about four or five users with the same profile pic. My question is actually a two part’er. One: Am I mistaken about one person operating or posing as several users? Two: If I am not mistaken, why would you do this?