Most click fraud articles thus far have involved PPC customers who swear there is click fraud arguing with search engines who claim clickfraud isn't much of a problem. BusinessWeek decided to investigate and talks with a whole bunch of people who actually make money click fraud'ing. They talk to individuals, networks, and technology developers.

Makes it a lot harder to believe the engines when they tell us how well they have things under control. Here's the key paragraph:

A BusinessWeek investigation has revealed a thriving click-fraud underground populated by swarms of small-time players, making detection difficult. "Paid to read" rings with hundreds or thousands of members each, all of them pressing PC mice over and over in living rooms and dens around the world. In some cases, "clickbot" software generates page hits automatically and anonymously. Participants from Kentucky to China speak of making from $25 to several thousand dollars a month apiece, cash they wouldn't receive if Google and Yahoo were as successful at blocking fraud as they claim.