How Click Fraud Could Swallow the Internet

Wired

Pay-per-click advertising is big, big, big business. So are bogus hits on Internet ads. It's search giants against scam artists in an arms race that could crash the entire online economy.
By Charles C. Mann

Stuart Cauff launched a charter-jet service in Miami Beach back in 2002. Being a 21st-century business, JetNetwork advertised on the Internet, especially on search engines. Anyone who Googled, say, "air charter Miami" would be greeted with the familiar list of search results and, in a separate place, a plain box of text with a blue hyperlink to JetNetwork's Web site.

Search ads were perfect for Cauff's business. His potential customers - a diverse group of celebrities, photojournalists, medical evacuees, and people who just needed to get away from or to Miami in a hurry - were scattered across the country. To reach this audience with traditional advertising, he would have had to buy time on scores of television and radio stations and space in just as many newspapers and magazines, something that only wealthy, established companies could afford. Even if Cauff could pay for the ads, the vast majority of people exposed to them wouldn't care about charter jets, so most of his money would be wasted. But with search-based ads, JetNetwork's name would appear, at least in theory, only before people who were actually interested in Miami charter flights.

Still, the ads were expensive. This kind of advertising is known as pay-per-click, because advertisers shell out money to a search engine every time a surfer clicks on their links. The price and placement depend mainly on how much the advertiser wants to bid for the search term - also known as the keyword in ad jargon. As other charter-air companies began PPC advertising, the cost of a click on a top-ranked ad rose to about $10 - in some cases as high as $30 - and there could be hundreds of clicks a month.

Which is why Cauff was infuriated when he discovered that up to "40 percent, maybe more" of the clicks on his keyword ads apparently came not from potential customers around the nation but from a single Internet address, one that belonged to a rival based in New York City. "If we get clicked fraudulently, it uses up our ad budget," he says. Advertisers usually set limits on how much they will spend, and search engines drop ads once they hit that limit. As a result, fraudulent clicking "literally pushes us off the page," Cauff explains. "And then our competition buys in at a lower price when we're not there."

Cauff was a victim of "click fraud," the illicit manipulation of keyword-based advertising. In this case, the scam appeared straightforward - one company clicked on a rival's search engine ads to drive up its costs. More complex is a second type of bogus ad click that exploits a second form of PPC advertising: ads fed to Web sites - anything from personal blogs to the sites of major corporations - by search providers like Google, Yahoo!, LookSmart, and, soon, MSN. The search engine indexes the content of the Web site and matches it with a group of relevant ads. (The most familiar form is Google's AdSense program - the sets of links labeled ads by goooooogle that show up on pages across the Internet. The advertisements that appear on Google itself are part of a separate but related program called AdWords.) Thus, bloggers who write about their air-travel experiences and choose to host such ads may find links on their . . .