Ad stacking is an ad setup policy violation wherein two or more layers of ads overlap one another in a single ad slot and only the topmost ad gets the chance to be viewed or clicked but each advertiser for every ad served still pays for the impression regardless of where they appear in the stack.
We have another article that talks about it here: https://www.monetizemore.com/blog/how-detect-stop-ad-stacking/
It is most often unintentional but will eventually hurt your reputation to advertisers and can lead to getting your account banned. PubGuru will report the ad stacking instances detected on your site and here are some steps to verify if it is indeed happening and address it accordingly.
Ad stacking instances are reported in your PubGuru dashboard.
Step1: Log in with your username and password
Step 2: On the left-hand panel, go to Policy Reports > Ad Stacking
Step 3: Click to expand and view more details
Step 4: You will see the list of Top URLs, Top Browsers, Top Page Widths where ad stacking was detected. To get more details on the exact scenario when the issue happened, export the report.
Step 5: The information on the report will allow you to easily replicate it. You won’t need to test each one of the reported URL + width. You can only select to test a few.
Step 6: Try to find the occurrence where your device specification matches the operating system, browser version, device, etc.
Step 7: Open the URL and adjust the resolution based on the reported width. The below example is using Window Resizer.
You may also use Chrome Developer Tools > turn on Device Toggle:
Then adjust the width:
Ad sizes could play a role, so pay attention to the sizes being flagged. For example, a unit configured as multi-sized is colliding with another ad unit only when it’s serving the bigger size.
In some cases, ad sizes are truncated by its parent div, it’s still considered as collision:
Step 8: Locate the ads reported. Are the ad units confirmed colliding or stacking?
-If yes, you can stop checking here and work on fixing it.
-If not, proceed below.
Step 9: Run PubGuru Ad Inspector. Check under the “Ad Units” tab. In the example below, the ad units are clearly stacked on top of each other. Compare it with the report on your PubGuru dashboard if they match.
Turning on Ad Overlay could help so you can easily identify the ads on page.
Step 10: Locate the ads reported and work on fixing it. You might want to also try another set of URL and width from the report in case you are unable to replicate it with the other.
Here’s the course that 300+ pubs used to scale their ad revenue.