Well, a few.
1. You need to have a Google AdSense account. If you don't have one yet, here is more information
2. You must have at least 50 posts on our forum before your ads will begin to appear. Once you reach 50 posts, ads will appear on every thread that you have started (even those you did inside of your first 50 posts).
3. Your AdSense code is displayed 75% of the time that one of your threads is viewed. Our ad is shown the other 25% of the time.
4. You must follow the Google AdSense terms and conditions. This means that you cannot discuss details of your earnings, and you certainly cannot click your own ads or encourage others to click your ads.
5. We might change some of the settings about how the ads are split up.