The other day we reported on the new beta project at AdSense that let's you filter ads out by category. Back then, it was rumored that Google allowed the advertiser to specify the category of their ads. That was wrong.
AdSenseAdvisor has come into the WebmasterWorld thread to clarify, saying Google controls those categories. AdSenseAdvisor said:
Google’s adserving technology determines the category to which an ad belongs.
This makes more sense and helps avoid the issue of advertisers maliciously miscategorizing ads.
Forum discussion at WebmasterWorld.