It takes a lot of time and effort to get a forum started.
Make sure you’re posting good content first. Get friends to post good content there too.
You’re going to see a huge ratio of lurkers to participants on any forum. CAP has almost 700 members I think, but if you count the number of folks who actually make posts in a given week, I’d imagine it’s a pretty small percentage of that. That doesn’t mean people aren’t visiting regularly and reading what’s going on at the forum.
Be sure to visit some other poker forums, legitimately participate there, and keep a link to your forum in your signature. Don’t actively promote your forum on another forum unless you use their billboard section, but do particpate intelligently in the discussion there and people will start to trickle over.
Hope that helps–good luck with your new forum!