Now in its third year, the Click Fraud Index monitors and reports on data gathered from the Click Fraud Network, which more than 4,500 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. Key findings from data reported for Q3 2008 include:

-    The overall industry average click fraud rate was 16.0 percent for Q3 2008. That’s down slightly from the 16.2 percent rate reported for both Q2 2008 and Q3 2007.

-    The average click fraud rate of PPC advertisements appearing on search engine content networks, including Google AdSense and the Yahoo Publisher Network, was 27.1 percent. That’s down from the 27.6 percent rate reported for Q2 2008 and the 28.1 percent average click fraud rate reported for Q3 2007.

-    Traffic from botnets was responsible for 27.6 percent of all click fraud traffic in Q3 2008. That’s up from 25.2 percent for Q2 2008.

-    In Q3 2008, the greatest percentage of click fraud originating from countries outside North America came from Russia (4.9 percent), France (4.8 percent) and the U.K. (3.5 percent).

“For the past two quarters the industry average click fraud rates seems to be hovering around the 16 percent level,” said Tom Cuthbert, president of Click Forensics. “Gains are being made by advertisers taking more action to proactively filter out fraud before it affects online campaigns. However, the growth in click fraud traffic from botnets continues to rise and it should be one of the top areas advertisers and the industry should monitor closely.”