The average click-fraud rate for the five industries studied was 14.1 percent in the quarter, compared with 13.7 percent for the first quarter, Click Forensics LLC said. The San Antonio company's Click Fraud Index for high-priced search terms was well above the average at 20.2.
The higher rate is an indication of the financial benefit of perpetrating click fraud against buyers of the highest-priced search terms, which Click Forensics classifies as those that cost $2 or more per click.
"Clearly, there's a financial incentive," Tom Cuthbert, president and chief executive of Click Forensics, said.
Click fraud is often used by competitors to drive up the online advertising costs of rivals. It's also used by some Web site operators to increase revenues. The activity is often automated through the use of computers.