A longer version of this story for Search Engine Watch members describes the legal options available to advertisers who suspect that they've been the victim of click fraud, and the steps required to gather evidence and supporting information to take action against it.
"Click fraud has gained a lot of notoriety in the last six months, certainly in the popular press," said Jeffrey Rohrs, President of Optiem LLC.
Some of the motivations of click fraud include financial gain, competitive advantage, revenge and blackmail.
Jessie Stricchiola, founder of Alchemist Media, began by describing the financial gain click fraud "flavor."
"Google's AdSense program, generally speaking, allows the owner/webmaster of any web site---large, small, legitimate, or fluff---to become an AdSense partner," said Stricchiola.
"Because approval and management of the AdSense program is primarily algorithmic and not human-edited as in Overture," she further explained, "there has been much room for abuse---basically webmasters setting up shop with web sites purely to host content for the delivery of AdWords.
These webmasters create their own artificially-generated traffic by automated means---namely hitbots."
Therefore, in this instance of financial gain, opportunities exist to use the Google AdSense program to generate direct revenue for the fraudster.
One way to get the top bidder out of the hot spot is to stop using their keywords (on your ads) and run up your competitor's bill.
There are two primary methods of generating invalid, fraudulent clicks: manual clicking (by humans) and automated clicking (by software).
"Additionally, the two primary initiators of click fraud are advertising competitors and CPC engine affiliates/traffic partners," Stricchiola explained.
"Overture has historically been more willing to disclose traffic data to the advertiser during the refund negotiation process, which has helped resolve some click fraud issues more quickly," said Stricchiola.