How about you hold a contest so that most popular and active forum gets free advertising. This would encourage people to get more people on aceboards so that they can get free exsposer and become even more popular. This would benifit you(makers of aceboard) as well as you get more people flocking over here and you can sell add prices on the most popular boards for more than you would at other lesser known boards. Its win win.

Seems like a good idea.