Ad fraud refers to any type of fraudulent activity in online advertising where the perpetrators make false claims to advertisers or networks for financial gain. This is often done through the use of bots that perform automated actions, such as clicking on adverts, watching videos or filling in forms, without any real human interaction taking place. The intention behind ad fraud is to get advertisers to pay for useless or misleading impressions and clicks, thereby compromising the effectiveness and ROI (return on investment) of advertising campaigns.

Ad fraud is a serious problem in the digital marketing landscape, as it not only leads to financial losses for advertisers, but also jeopardises the integrity of the entire online advertising ecosystem. Various technologies and methods have been developed to detect and prevent ad fraud, including the use of specialised anti-fraud software and advanced algorithms that can detect and filter unusual activity.

The forms of ad fraud are diverse and range from simple click fraud to complex schemes such as ad stacking, where several adverts are stacked on top of each other so that only the top one is visible to the user, while payment is made for all of them. Due to the continuous development of ad fraud methods, constant monitoring and adjustment of anti-fraud measures is essential.