Google Revenue Sharing
 

See example on http://www.namepros.com

Anyone with a Google account can go into their forum CP and enter their Google Publisher ID. All threads will display a Google ad somewhere on the page. When a user participates in a thread, then there is a chance their publisher ID will be used to display the thread. There would be a 50/50 split between the site and the users, meaning 50% of the time my own ads would be shown, and then 50% of the time the participating posters' ads would be shown.

This is not against the Google TOS. Also, there is less of a chance of fradulent clicks than you would think, because we would make it clear that if someone has participated in a thread and they click just to click, there's a chance its THEIR ad, which would result in them getting kicked out of the program.

This would be easy to hack and would be cool too. However, if an adsense publisher gets kicked out of adsense, ALL domains that were associated w/ that publisher get their domain banned from using adsense. Unless that forum spoke to google themselves and got assurances?