Private Rooms are sort of like Private Messages with more people. Several chatters can interact, and no one else in the community can participate.
To create a Private Room:
To enter a Private Room created by someone else:
Private rooms exist only as long as someone is present. In other words, when the last person leaves the room, it goes away. If that sounds confusing, think of it this way: When you're participating in an Instant Message exchange with someone, a connection exists between the two of you - almost like a small personal chat room. When you both say goodbye, that connection is gone until you reestablish it.