Some interesting things from an article from the guy who wrote the Slash book, Building Online Communities [Oct. 21, 2002]:
You’ll know you have a healthy community when users comment publicly that “this is the best site I’ve ever used,” “I came here because of the goal, but stay around because of the people I’ve met,” amd “No other place on the internet is like this.” Happy users tend to talk in terms reminiscent of Manifest Destiny and settlers in a little-p paradise. It occurs in almost every healthy, somewhat-social community.
You will never please some users. A few will stick around only to see your next mistake. They tend to be vocal. Their pessimism doesn’t make them wrong, but it can be grating. Accept that they are a minority, expect them to make concrete suggestions and honest criticisms occasionally, and try not to be surprised that they don’t leave. (Most people who leave do so quietly.)
Start with a list of unacceptable behavior. … Create a list of consequences, which may range from warnings to suspensions to expulsions. … Choose your response before it’s needed.