More details of the keynote by Rob Pardo at the Austin Conference:

“The beta test for us is not about finding bugs. It?s not really about getting a lot of game feedback. it?s about stress testing from a technological and gameplay level. We encourage our testers to exploit the hell out of the game. In our RTS beta tests, people always get upset that we run a ladder in the beta test, because the guys on top are exploiters. But that?s the point ? we want to see who the top ten exploiters are so we can look at their games!”