Why doesn't my Yahoo Messenger chatroom service work?

In the yahoo messenger menu you can choose to join a chat room. I tried it, and I get to the room, but the only residents are the room moderator (which is some authority figure working for Yahoo), and I. I tried over 20 other rooms, which I deduced would likely be the most popular, and same thing. Where are all the people on Yahoo chat? And how do I join the room??