Advertising fraud refers to deceptive practices that manipulate advertising metrics to create a false impression of performance. This can include activities like click fraud, where automated bots generate fake clicks on ads, or impression fraud, where ads are displayed on non-human traffic sites. Such actions lead to wasted advertising budgets and skewed data for marketers. Another common form of advertising fraud is ad stacking, where multiple ads are layered on top of each other, causing only the top ad to be visible. This misleads advertisers into believing their ads are being seen, while in reality, they are not reaching potential customers effectively.