Google AdSense: Forum optimization study

We are currently working to improve the performance of Google ads on forum
sites and would like to invite you to participate in our forums
optimization study. Participation in the study will include the option for
you to customize your AdSense code to rotate through several positions in
your forums in order to find the best performing position(s). If you are
comfortable with modifying your forum code, you can also extend the
rotation to another targeting option we are beta testing for forums.

found it here:
http://www.vbwebmaster.com/forums/showthread.php?t=929

Great news for my forum on RockaRolla.gr