The culprit

A new analysis report has been released showing click fraud grew faster than before in the second quarter of the year, reports Forbes.

According to the report from Click Forensics, fraudulent clicks rose 15.8 percent in the second quarter of 2007. At Yahoo and Google the problem is even worse, with fraudulent clicks accounting for 25.6 percent of ad clicks.

The report was compiled by analyzing the click logs of over 4,000 advertisers and shows that malware-infected PCs are an increasingly popular tactic of the fraudsters. In the second quarter, Click Forensics says botnet-driven fraud doubled, becoming the prime mover of the overall growth.

Both Google and Yahoo claim the click fraud problem, while real, is not nearly as pervasive. Yahoo assumes 12 to 15 percent of clicks will be fraudulent while Google says the number is less than 10 percent.

Outside analysts and advertisers complain, though, that neither company provides enough data to allow them to see if that's actually the case.