The problem was with a change made to the show_ads.js file that is downloaded for every AdSense ad unit view. The problem was first reported on August 11th, but it took until August 15th for the problem to be resolved. More details on the specifics of the problem at JenSense.
Introducing SES Online
Want to view one of the sessions you missed or listen to an especially informative presenter a second time? SES New York sessions are available for purchase on ClickZ Academy's new e-Learning site. SES is now Online!