Keep the community's Title, Forums, Topic of Discussions and Discussions...
interesting and
diverse.
If you call it the Online Chess Players Community and rarely discuss anything besides En Passant, it will likely quickly evolve into a chess club.
Yahoo touted an audience increase to 120 million unique users in December of 1999, doubling December 1998's mark of 60 million, as well as a registered base of 100 million users by the end of 1999.
I've been using yahoo.com for years and I rarely see a week or two go by that something hasn't changed for the better, it seems in the world of Cyberspace the old rule of "If it ain't broke don't fit it." doesn't apply.
There are some resources below, you've probably read many of these moderator tips but you might pick up on something that may help further answer your question.
harvard.edu Moderator Tips for Building Online Communities
Moderator Guidelines, By Lisa Kimball, Metasystems Design Group
auburn.edu Tips for Working in Groups (Not directly related but great tips nonetheless)
There are also some links to good tips in one of the other forums on TechSoup here:
Hope this helps¸ Sean