I've been looking into creating my first forum soon and I have been wondering what the best way to monetize it would be. I have heard that it's extremely hard to get good results with AdSense on a forum. Is this true? Are CPM programs better even if they have a low pay rate?

Adsense is generally better in the beginning b/c your stats will be so low that any CPM network probably won't take you.

It really depends on your niche.

I run adsense on my forum. It gets around 200 uniques a day, and makes me $1/day if I'm lucky.

Adsense isn't the best for a forum but like rex said you may have a hard time getting CPM ads at first. Once you get some good traffic then consider a CPM network.

I would like to say premium memberships can be good, even early on to help build loyalty and a strong base membership. Don't leave out private advertisers either, especially if the site is in a strong niche.