Now in its third year, the Click Fraud Index monitors and reports on data gathered from the Click Fraud Network, which more than 4,000 online advertisers and agencies have joined. The Click Fraud Network provides statistically significant industry PPC data collected from online advertising campaigns for both large and small companies across all the leading search engines.
The overall industry average click fraud rate rose to 16.6% in fourth-quarter 2997, up from the 14.2% click fraud rate for the same quarter in 2006 and 16.2% for third-quarter 2007.
The average click fraud rate of PPC advertisements appearing on search engine content networks, including Google AdSense and the Yahoo Publisher Network, was 28.3% in fourth-quarter 2007--up from the 19.2% average click fraud rate for the same quarter in 2006 and 28.1% for third-quarter 2007.
The 2007 industry average click fraud rate grew by 15% over the industry average click fraud rate for 2006. Fourth-quarter 2007 click fraud traffic from botnets was 15% higher than click fraud traffic from botnets in third-quarter 2007. The greatest percentage of click fraud originating from countries outside North America in fourth-quarter 2007 came from India (4.3%) Germany (3.9%) and South Korea (3.7%).