Click fraud has been an issue of controversy for a long time. Google and Yahoo know it is a big problem, but even those search behemoths seem unable or unwilling to squash the problem for good. Some have taken matters into their own hands, such as Click Forensics, a startup that seeks to find where all the fraud is coming from and help put a stop to it. The company got a leg up recently, with a cash infusion. They have received a $10 million investment, which they plan to use for continued development of click fraud discovery tools.
Google and Yahoo obviously have no particular interest in helping out a company like this, but the many advertisers that rely on the two giants definitely do. In 2006, Click Forensics claimed that as much as 14% of click-throughs were fake, which would cost advertisers a lot of money.