Impression fraud is when falsely generated ad impressions affect an advertiser’s account. In the case of click-through rate based auction models, the advertiser may be penalized for having an unacceptably low click-through for a given keyword. This involves making numerous searches for a keyword without clicking of the ad. Such ads are disabled automatically, enabling a competitor’s lower-bid ad for the same keyword to continue, while several high bidders (on the first page of the search results) have been eliminated.
Is impression fraud a serious crime? Yes!
In 2004, California resident Michael Anthony Bradley created Google Clique, a software program that he claimed could let spammers defraud Google out of millions of dollars in fraudulent clicks, which ultimately led to his arrest and indictment. Charges were later dropped because in order to pursue the case Google may have been forced to reveal secrets they wanted to remain
Proving click fraud can be very difficult, since it is hard to know who is behind a computer and what their intentions are. Often the best an advertising network can do is to identify which clicks are most likely fraudulent and not charge the account of the advertiser. Even more sophisticated means of detection are used, but none are foolproof.