Mryang,

Although you asked about advertising, don't forget that you can greatly monetize your forum by setting up special member groups and special access subforums. People often can't resist being rated, and perhaps your visitors could be grouped according to skill or achievement level, such as novice, intermediate, competition, etc. They could either pay for just forum support bragging rights (with custom icon), or get to enter exclusive subforums, etc.

Just an idea that has worked really well with my forum.

--E.