What is Ad Stacking?

In digital advertising, each time an ad is shown to the user, it counts for an impression. These impressions are generated by both organic and paid marketing. As the ad slots are limited on a webpage or a mobile application, fraudsters often stack ads one on top of another. Sometimes, they even stack multiple ads together. The user only sees the top ad, and generally all the ads below the top ad counts for impressions but are not seen by user in reality.

Ad stacking is rampant and still happens across many platforms.
 

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How does Ad Stacking work?

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Ad Stacking happens exactly how it sounds, multiple ads are layered one on top of the other in ad stacking. The fraudsters literally layer ads on top of each other in the same ad placement, yet only the ad on top is visible to the user. 

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Despite the fact that the user only sees the ad on top, marketers and advertisers are charged for all of the misleading and false ad impressions and clicks obtained from the advertisements underneath. Advertisers are still charged for the unseen or un-clicked ads since they still load correctly, and meet the requirement of having one pixel shown for at least half a second (a common metric in the digital advertising industry). 

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The goal of this activity is to charge publishers and advertisers for the all the stacked ad's impressions and clicks.​