JOHN Carreras was once a contented Google advertiser. He used text advertisements that appeared alongside searches to bring people to his trade exhibition website. He happily paid Google a few cents for every referral, believing that anyone who clicked through to his site from Google was a likely customer. But then he attended a conference in LasVegas, and he noticed something strange: the number of Google referrals he was getting dropped dramatically, only to rise again once the conference was over.

Carreras became convinced the "missing clicks" weren't from customers but from his competitors, who had been in Vegas with him. He believed his unscrupulous rivals whiled away their office hours clicking on his Google ads, knowing that every tap cost him money.

If you add in a second kind of scam, where people earn themselves a little money from Google by clicking on ads they're hosting on their sites, you can see the potential for malice. Click fraud, as it's called, is acknowledged by Google as a problem: last year, Google's chief financial officer, George Reyes, described it as "the biggest threat to the internet economy".

While Google Labs, as the company calls its development division, turns out new products at a cracking pace, Google remains largely dependent on just one source of income: advertising. Google would never admit to being uneasy about that reliance. Why should it? Advertising is doubling the company's revenue every year, and is expected to generate almost $10 billion this year. But for all the undoubted strengths of its pay-per-click system, some worrying vulnerabilities have emerged.

Marissa Mayer, the company's vice-president of search products, is reassuring. She calls it "a serious problem for us, but also a very solvable problem".

In principle, the company will not charge its advertisers for clicks that aren't from genuine potential customers. Typically, Google is hoping to use technology to detect suspicious click patterns.

LOL, how they can ever stop a competitor and his friends with smartphones, who hit every WiFi spot known to man, is beyond me!

I did read on the Black Hat SEO Forum that companies were offering a "click on your competitors service"