Click fraud is a type of Internet crime that occurs in connection with pay per click online advertising when an automated script or computer program imitates a legitimate user of a web browser clicking on an advertisement, for the sole purpose of generating a charge per click without having actual interest in the target of the ad's link.
Bots are commonly used to execute click fraud because they can easily be directed to send web requests that represent "clicks" on the internet advertisements of certain affiliates. These additional "clicks" boost their affiliate revenues paid by the advertisers. Because the systems infected with bots generally belong to real people and are usually well distributed across the internet, it is very hard to distinguish legitimate clicks from automated, bot-generated clicks. Click fraud activity generates large volumes of revenue for attackers and their customers.
Click fraud is a crime in many jurisdictions, including California, where it is a felony.