Patrick O'Keefe

“You'll notice that I said guidelines and not rules. Guidelines allow for some flexibility, some discretion. Rules are more likely to be enforced in a hard and fast manner, which can leave little room for interpretation and will probably lead to you having to deal with more nutcases who insist on reading them fifty times backward and forward in hopes of finding an angle where they think you are being inconsistent. Your user guidelines are a key communication tool for you. They are a type of vision statement for your community. By putting your expectations of users in writing, you are letting everyone know what your vision is for your community. By communicating this, people will know what they are in for and will either get behind you (and participate) or get away from you. Either way, they will at least know what your community is all about, and having this level of communication is vital to your success.”
― Patrick O'Keefe, Managing Online Forums: Everything You Need to Know to Create and Run Successful Community Discussion Boards