when you sign up for the free forum do you get a account on your site where you can edit the footer? wel i was thinking in your account you could have a referal page with your referal link and a table with the stats of how many people you refered (click throughs to site, how many signed up to forums)
Then when you have enough points you could use it in exchange for ad free ect.
obviously there is a problem you could have admins getting there members to sign up to forums for the sake of it to get points but you could say for example you get one point for a click through and 5 points for a click through if someone signs up to a forum that stays active for over a month.
do you think its a good idea and could it be done??
Sorry, it's impossible for next releases. But i keeps in our records, i'm not sure it will be done but it will be in our new features list when we are going to release new version/release in feature.