If you use PPC advertising and are in a highly competitive market, you can't afford not to read this.

You already know that if you're adventurous enough to run your own pay-per-click advertising campaign--e.g., Google Adwords, or Overture--you should watch your site traffic like a hawk, and keep all server logs for the inevitable day when you get a flood of suspicious hits that don't convert, and you need to get your money back. But just when you thought it was safe to go back in the PPC waters, a new shark has been sighted.

According to a recent article in theregister.co.uk, you now have another kind of click fraud to worry about. Or perhaps we should start calling it "no-click fraud." Unlike every other kind of click fraud where nefarious website owners click the advertisements on their sites or nefarious competitors click on your advertisements to try to bankrupt you, this new breed of click fraud doesn't click at all. Instead, the fraudsters launch thousands of searches on a specific keyword you've bid on--and don't click. This drives down your click-through rate, which eventually leads to all the advertisements targeting that keyword getting pulled. With all the competing advertisements pulled, your competition can then waltz in and get top billing on a competitive keyword for five cents a click.

What Is To Be Done about this New Click Fraud Menace?

Tracking this form of click fraud may be more difficult than with other forms, since your server logs won't be any help when the criminal has never visited your site. Still, as with the other forms of click fraud, one of your best defenses is to monitor your click-through rate, and look for sudden changes. Only now you'll have to watch out for sudden drops as well as sudden spikes.

If you've been a victim of this kind of click fraud, or think you may have been, we'd love to hear your horror story, along with how Google responded (or didn't respond). Of course, if you don't want us to share it with our readers, you can trust us to keep a secret.