Ad stacking is a type of mobile ad fraud that involves layering or "stacking" multiple ads into a single ad slot. Scammers can engage in ad fraud in a number of ways. Ad fraud can be a confusing topic for a number of reasons:

- It's hard to gauge how widespread it is, because the whole point of ad fraud is to deceive metrics and analytics.

- Little is known about how it actually affects advertisers.

- Companies that sell digital advertising have no real incentive to clean up or execute on it, because they also make money from it.

For the purposes of this article, we will focus on the second reason.

The Plan

First, the publisher creates a site. On this site, they include ad space that they will sell. They then turn to ad exchanges, agencies, and direct sellers to sell space on those pages. When a person visits the site, the page loads and displays their ad in these areas.

What you don't see are scammers using ad stacking. While users can only see the ad at the top, advertisers who stack multiple ads below will still be charged for false impressions. For example, if a user clicks or views the top ad while other ads are stacked below it, that means impression will be reported for each ad in the stack.

Publishers then charge all advertisers to display their ads, even though most ads are never seen by real customers. Ultimately, by stacking ads, crooks steal ad budgets from advertisers and boost ad revenue for publishers who may be participating in the plan.

‍The Impact

Not only do advertisers pay, but their metrics are skewed to show too many impressions. They have no way of knowing if their ads were actually shown to customers, or how many of those impressions were genuine ad overlays, leading to wasted ad spend for marketers and skewed campaign data. To make matters worse, many of these scam sites use scripts to get bots to "view" ads to further increase the amount they receive from advertisers.

Scammers pull huge sums of money out of advertisers' pockets every day. While there has been some talk of cleaning up digital advertising, it's mostly up to individual companies to focus. Unfortunately, there are no complete defenses against many forms of ad fraud.

The Solution

While there is no complete solution to problems like ad stacking, you can reduce the impact of ad fraud on your ad budget and eliminate certain types of ad fraud altogether.

Here are some tips:

- Ask questions. If you're not sure whether your ad campaign will have an impact, ask your ad platform or publisher to investigate.

- Create periodic reports. Check your campaign frequently for any anomalies. Request a report from your publisher to see traffic sources​​

- Try Activity Scoring. Use technical tools to review your campaigns and make sure your ads are actually reaching real customers.

- You can prevent all of this with Protify's ad fraud analysis and protection system. Our solutions help prevent possible ad fraud by tracking and monitoring your ad campaigns.