Google is strict on how you get people to click on ads, and if google finds out a site is giving incentives to clicking on an ad, Google will terminate the contract with brainking. (Which a "contest" to see who clicks it the most would most defently be a no-no.) If Fencer could, he would probable put a big "CLICK HERE TO SUPPORT OUR SITE", and also encourage all users to click on a banner once or twice a day - but again, google frowns on this.