Guidelines

Board Guidelines are an essential part of a forum. If you don't post the board guidelines, you will definitely have many mistakes. What are some rules which are very important for you and you have seen them in many communities? How often do you update them? Share your thoughts with us.
Personally, I always write about the moderation policy and about the off topic posts. I don't want to have a forum with millions of off topic posts / spam. I don't usually update them because the members will possible get confused.