|This article does not cite any references or sources. (September 2014)|
A click farm is a form of click fraud, where a large group of low-paid workers is hired to click on paid advertising links for the click fraudster (click farm master or click farmer). The workers click the links, surf the target website for a period of time, and possibly sign up for newsletters prior to clicking another link. For many of these workers, clicking on enough ads per day may increase their revenue substantially and may also be an alternative to other types of work. It is extremely difficult for an automated filter to detect this simulated traffic as fake because the visitor behavior appears exactly the same as that of an actual legitimate visitor.
Pay per click providers, including Google, Yahoo!, and MSN, have made substantial efforts to combat click fraud. Automated filters remove most click fraud attempts at the source. In an effort to circumvent these filtering systems, click fraudsters have begun to use these click farms to simulate actual visitors.
The first method is by hiring competitor fraudsters to deplete the advertising budget of the competitor so that they will be able to have their ads shown in higher pay per click rankings at a lower cost. In this case, the competitor is weakened instead of being outbid in the pay per click bidding system. The investment on the click farm made by the fraudster is only a very small fraction of the amount lost by the competitor.
The second method is by hiring the click farm workers to click on ads on the click farmer's own site. This way, the money lost by the advertisers is gained by the click farmer rather than by the search engines and content networks like it is in the first method.