Are there any "set" hours for the chat room?
I think it would be a good idea to have one or two official times per week so the maximum amount of people can join.
Maybe something like every Mon. and Wed. at 8:00 PM eastern/5:00 PM pacific. Or Tues/Thurs. (?)
I visit another chat room, with the official chat periods of two times per week, and it works out well.