People use it for all purposes, some private discussions in private rooms, some general discussion in the general room. If you want to chat with someone, the best thing is to simply open a new window, go into the room and remain their. When someone else comes in, instead of thinking nobody wants to chat, they will see you and if you haven't checked it you will be marked with an away sign, which allows others to know your there but just not monitoring at that time.

If you check back every 5 minutes or so, you will likely find someone else has come into the room and will be there to chat with you.

Also as mentioned above, standing chat time as an organised group.