It is possible. There are no chat rooms, you can only chat one on one.

Look in the search screen. Whenever there is a smilie face in the chat column, press 'chat' (either the button, or the choice in the right click menu) Same thing on the upload and download screens.

This will open a new chat window. It does work, it's just that a lot of people don't respond. I HAVE chatted with people before, one of them turned out to be someone I know! What are the chances of that?