The joint campaign will allow the three major search engine players — who tally a combined 86 percent market share, according to comScore Media Metrix — to share information to better identify and measure click fraud.
Smaller search engines Ask.com and LookSmart have also announced plans to join the alliance.
While there are several forms of click fraud, the practice generally describes a situation where merchants are consistently over billed for repeated fruitless clicks.
According to some advertising industry estimates, overcharges could be as high as $1 billion dollars industrywide for the past four years.
Google and Yahoo, which dispute those numbers, attribute the eye-popping estimates to class-action lawyers eager to poach a growing industry.
In March, Google agreed to pay $90 million to settle a click fraud lawsuit.
Yahoo settled its case in July for $5 million.
As Internet advertising continues to grow through programs such as Google AdSense, estimates of click fraud could soar even higher. Google, for example, reported $4.7 billion generated from online ad revenue through the first half of 2006. The company said it realized a first half profit of $1.3 billion on that revenue.
One way the alliance hopes to stem the tide of click fraud is to come up with a comprehensive definition of the practice, according to John Slade, who directs click fraud defenses for Yahoo, adding that doing so will be a “game-changing step in measuring and fighting click fraud.”
According to NYU professor Alexander Tuzhilin, who was given access to Google’s internal monitoring systems, defining and finding click fraud won’t be easy because it is nearly impossible to tell whether users click ad links out of malice or curiosity.
"In some cases, the true intent of a click can be identified only after examining deep psychological processes, subtle nuances of human behavior and other considerations in the mind of the clicking person," Tuzhilin said.
It may take a year or more to finalize the guidelines for defining click fraud, Interactive Advertising Bureau CEO Greg Stuart said, adding that the decision to begin the process reflects the industry’s “commitment to being the most accountable advertising medium and providing marketers with the highest level of transparency.
