Jackie Long

Let’s talk about ad stacking

Ad fraud is a buzzword that hovers around digital advertising, but many people have no idea what it is or how it happens. We examine how ad fraud works through the specific example of ad stacking.

Ad fraud can be a confusing topic for a lot of reasons:

  1. It’s hard to measure how widespread it is because the whole point of ad fraud is to fool metrics and analytics.
  2. There’s not a lot of awareness about how it actually impacts advertisers.
  3. There’s no real incentive for the companies selling digital advertising to clean it up or enforce it because they make money off of it too.

For the purposes of this article, we can’t do much about 1 or 3, so we’re going to focus on that second reason. Here’s a quick overview of how ad stacking – one form of ad fraud - works.

The Scheme

To start, a publisher creates a site. On that site, they include advertising space they will sell. They then turn to ad exchanges, agencies, and direct sales to sell space on those pages. When a person comes to the site, the page loads and shows them ads in those spaces.


(Note: At this point, you’re probably saying, “but that’s exactly what supposed to happen.” And you’d be correct.)

What you don’t see is that each ad space is actually loading several ads, stacked on top of each other.



Only the top ad is visible, but many ad exchanges and agencies register each ad as being viewable because they loaded correctly in the frame and meet the requirements of having one pixel shown for at least half a second.

(Note: Yes, that is in fact a standard metric for many digital advertising companies.)

All advertisers are then charged by the publisher for serving their ad despite most ads never having been seen by the real customer.

The Impact

Advertising companies not only get charged, but also have their metrics skewed to show too many impressions. They have no way of knowing if their ad was ever actually shown to a customer or how many of those impressions were real. Even worse, many of these fraud sites use scripts to have bots “view” ads to further increase the amount they receive from advertisers.

Companies continue to lose huge portions of their advertising budgets to schemes like these. While there has been some talk about cleaning up digital advertising, it still falls mostly to individual companies to be on the lookout. And, unfortunately, there is no complete defense available for many forms of ad fraud.

The Solution

While there is not a complete solution for issues like ad stacking, you can reduce the impact of ad fraud on your advertising budget and completely cut out certain types of ad fraud.

Here’s a few tips:

  • Ask questions. If something about your metrics doesn’t look right, ask your agency or ad platform about it.
  • Compile regular reports. Check up on your campaigns often to look for anything out of the ordinary.
  • Try campaign scoring. Utilize technical tools to audit your campaigns and make sure your ads are actually reaching real customers.
  • Use NS8 Protect's integration with Google Analytics to block bots from your retargeting campaigns and focus on high-value traffic in future campaigns.
  • Do more research. Check out our intro guide to ad fraud or our detailed tips for protecting yourself against these threats.
About the author
Jackie Long

Jackie is a Content Specialist at NS8. With a varied background and over 6 years of content creation experience, Jackie works hard to provide a compelling range of informative articles.

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