The recent publication of the quarterly figures on click fraud by US firm Click Forensics has sparked the ongoing debate again between search engines and the growing number of monitoring companies, who accuse each other of misleading data and incorrect interpretations of click fraud within the PPC advertising market.

The new Click Forensics data suggests that the average click fraud rate in the 2nd Quarter of 2007 was 15.8%, although the big networks - Google and Yahoo! - accounted for 25.6% of all fraudulent traffic during this period. Yahoo! responded to say that advertisers hadn't been charged for 12-15% of all clicks through its network. Google questioned the whole methodology being used by Click Forensics and say that the figures are being inflated incorrectly to generate concern amongst advertisers (and to promote the benefits of the Click Forensics service).

Of course both sides of this argument have their own agendas and are unlikely to agree a correct definition and methodology to track fraudulent activity. There will always be an element of wasted traffic that's impossible to track, but getting an accurate view of identifiable fraud would need closer cooperation and the sharing of data between both parties, which is unlikely to happen.