Those guilty of Google pay-per-click fraud are getting sneakier by the day. Ben Edelman, a Harvard Business School professor, has discovered one of the more “diabolical” click fraud schemes out there.

He summarized it by saying:

Here, spyware on a user’s PC monitors the user’s browsing to determine the user’s likely purchase intent. Then the spyware fakes a click on a Google PPC ad promoting the exact merchant the user was already visiting. If the user proceeds to make a purchase — reasonably likely for a user already intentionally requesting the merchant’s site — the merchant will naturally credit Google for the sale. Furthermore, a standard ad optimization strategy will lead the merchant to increase its Google PPC bid for this keyword on the reasonable (albeit mistaken) view that Google is successfully finding new customers. But in fact Google and its partners are merely taking credit for customers the merchant had already reached by other methods.

He went into detail about all of the about how he figured it out and pointed to a perpetrator, Trafficsolar, which he blames InfoSpace for connecting Google to. He goes on to say that Google should drop its relationship with InfoSpace and other partners with their own chains of partners. This makes it even harder to monitor. Click Forensics Steve O’Brien doesn’t think it’s worth going that far. “A better solution would be for Google and InfoSpace to deal only with reputable partners who provide verified, audited clicks to ensure advertisers get what they pay for,” says O’Brien.