Thanks. I can see the logic. OTOH, doesn't this require perfect efficiency and for all bidders to know perfectly their ROI, etc.? Any holes, unintentionally ir

Thanks. I can see the logic. OTOH, doesn't this require perfect efficiency and for all bidders to know perfectly their ROI, etc.? Any holes, unintentionally irrational behavior, etc. and the fraud "leaks" into the price, right? So, for instance, any "unprofitable" advertising on behalf of any participants would seem to automatically cause the fraud to be reflected in the price. Based on personal experience, I would guess that there's a pretty long tail of advertisers who never realize an ROI while spending a considerable sum seeking it! Even those that eventually profit likely spend a good bit of money ramping up, all the while paying for fraud in the process and helping to support a fraud-inflated CPC overall.