Google has updated its AdSense ad policies, no longer permitting the use of such ads on pop-under pages.
This decision was made because the company believes ads on pop-under pages do not provide a good user experience.
“Pop-under ads can be annoying as well, as they will “pop under” your window, so that you don’t see them until you minimize your browser. We do not believe these ads provide a good user experience, and therefore are not suitable for Google ads.”
Further, Google is no longer permitting the use of its ads on sites that trigger pop-under pages, even if the pop-unders do not contain an ad.
In other words, if you want to stay in Google’s good graces and continue displaying AdSense ads, it’s best to refrain from using pop-unders.
It’s the responsibility individual site owners to ensure their site is compliant with Google’s policies.
If found to be in violation of Google’s ad policies, the company may ban the use of AdSense ads on a site with or without warning.