According to click fraud monitoring firm ClickForensics, the overall industry rate hit 16.2 in the third quarter of the year.

This is an increase on 13.8% for the same period in 2006, and is also up on the previous quarter’s average of 15.8%.

Meanwhile, the click fraud problem has worsened for ads on search engine content networks including Google AdSense and the Yahoo Publisher Network, increasing by roughly 3% to 28.1% in Q3 – almost 10% higher than in Q3 2006.

According to ClickForensics CEO Tom Cuthbert:
“Click fraud activity continues to grow especially on made for ad sites, parked domains and on the content networks, advertisers, publishers and search engines need to take notice because content networks are becoming the fastest growing source of click fraud. Ensuring their quality is essential for the pay per click advertising market to continue its growth.”

These figures are likely to be disputed by Google, which has previously said that the click fraud estimates of independent monitoring firms like ClickForensics exaggerate the extent of the problem.

Google’s Senior Product Manager Shuman Ghosemajumder has said that the search engine filters out less than 10% of clicks as invalid, and that advertisers are reimbursed for fewer than .02% of clicks.

Cuthbert believes that this debate is good for the industry though:
“Sometimes the dialogue with Shuman or Reggie Davis from Yahoo can be somewhat contentious, but I think it’s healthy for the entire industry…we’ll continue to keep the pressure on to make sure they get the transparency they need. But we need to bring the entire community together–from the publishers, to advertisers, to the engines–to solve this problem.”

There is no doubt that all advertisers should be aware of PPC click fraud, but carefully managed PPC campaigns should always deliver a positive ROI, including any costs incurred for fraudulent clicks.