Click Fraud

T oday, Web search engines are the primary method for millions of users throughout the world to access information on a topic, navigate to Web sites, keep up with the news, and shop online. Most major search engines generate revenue via sponsored search, a process whereby content providers pay for traffic from specific links the search engine's display in response to user queries. Search engines typically display these links alongside non-sponsored links, also known as organic or algorithmic links. Sponsored search has become an integral part of the business model of most search engines and many online retailers, generating billions of dollars in revenue each year. As such, it plays a critical role in financing the " free " search provided by search engines that has become indispensable to many Web users. Given the profound impact of sponsored search on Web content access, anything that compromises the process would have significant social, economic , and political repercussions. Click fraud, which involves the intentional clicking on sponsored links with the purpose of gaining undue monetary returns or harming a particular content provider, has the potential to do just that. Click fraud is one of the fastest growing problems on the Web, according to search-engine marketing firm iProspect (www.iprospect.com). It can take various forms, but the result is usually the same: Content providers pay for unproductive traffic generated by perpetrators who repeatedly click on a sponsored link with no intention of giving value to that provider. To understand click fraud, it is necessary to define some key terms. In this context, value is the use of information, employment of a service, purchase of a product, or execution of a transaction by a Web site visitor that is consistent with the content provider's goal. A sponsored result is the title, text, and other material associated with a particular sponsored link. A sponsored link is a URL serviced by a search engine in response to a query in a search-engine results page (SERP) or in a contextual manner in a relevant Web site or e-mail. A click is the act of initiating a visit to a Web site via a sponsored link and can be either • valid—an intentional click that has a realistic probability of generating value once the visitor arrives at the Web site; or • invalid—a click on a sponsored link that has no probability of generating value. Invalid clicks can …