Biggest Threat to Internet Economy So says Google’s chief financial officer, and he ought to know.Google CFO George Reyes, speaking at an investor conference sponsored by Credit Suisse First Boston, said that click fraud could potentially threaten his company’s whole business model. By extension, click fraud threatens Yahoo!, eBay, and other firms that depend on revenue from cost-per-click advertising. What happens in click fraud is that scam sites set up for the sole purpose of hosting ad links, then either humans or software click on those ad links to steal revenue. Some observers estimate that click fraud may be responsible for as much as 20 percent of all clicks on paid search ads. Reyes said that click fraud costs his company and others who depend on this type of paid advertising “tons of money.” It could seriously spoil things for the rest of us.