Theres an easy way to bring people to bet their vg$ to more risky titles: If the overall accuracy for a title is very good, than it reduces the amount of VG$ you get in return. At the moment (according to the rules http://vgchartz.com/predictions/rules.php) the accurracy is divided by 50 to calculate your winnings. For a net profit you need at least 50% accuracy. If you instead use the average accuracy over all participating members it would result in a higher risk to bet on easy predictable games. Say a easy to predict game (WiiFit) will have a average accuracy of 90%. In this cas you need 90% to get a profit. On a harder to predict game (say DMC4) the average accuracy is 60%. You get a profit if you have a accuracy higher than that. If it works like that, people wouldn't bet the most vg$ on easy predictable stuff.