Traffic sourcing: Digital fraudsters have developed bot networks that pretend to be human traffic. These fake audiences are then sold in bulk to unaware publishers for fractions of a cent.
Ghost sites: Fraudsters build fake websites to serve as hosts on programmatic ad platforms and exchanges. When ads are posted on ghost sites, fraudulent bots perform click fraud and generate fake impressions, for which the fraudsters are paid based on the cost per click (CPC) or CPM.
Domain spoofing: In this type of fraud, an irrelevant site of poor quality is deliberately misrepresented as a high-value site for programmatic bids. This allows fraudsters to gain far higher CPMs than the irrelevant site would actually command. The perpetrators then flood the low-quality site with bots and collect the resulting payments.
Ad stacking: This tactic generates multiple impressions from a single page view by stacking multiple ads directly on top of each other. While only the topmost ad can be viewed, each of the underlying ads also counts as an impression.
Pixel stuffing: This type of ad fraud vastly multiplies the number of ads that can be presented on a website. It works by stuffing an entire ad into a single pixel on screen, rendering it invisible to humans.
Ad injection: This is when fraudsters inject ads into a website without the publisher’s knowledge or approval. Injected ads can pop over, under, or even replace existing ads (just like ad stacking). Ad injection affects publishers’ brands and their viewability scores.