I'm new to this forum, but am a member of other forums online that have chats. Thought I might give you a recommendation. Out of all the forums I'm on, the only chats that ever have anyone in them are the ones that set up a scheduled meeting time. I'd try to poll the users interested in using it as to a day and hour, then have that be the weekly meeting time and put that in a sticky. Otherwise what you'll see is everyone that is interested will go in chat, stay for a couple minutes, no one's there so they leave. One after another. If you are more interested in a daily chat time, first go with once a week and then when you have a few regulars expand it. Hope that helps.
-MJ