In the “about time” category, Google has updated the ad policies in AdSense to disallow the use of ads that use pop-under pages.
This is another step in the journey to make ads less annoying for users. In Google’s words: “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.”
For those that are unaware, pop-under ads open a new browser window hidden under the active window. Pop-unders are stealthy as they do not interrupt the user immediately and are not seen until the covering window is closed, making it more difficult to determine which web site opened them.
Now that this exclusion has been added to the ad policy, any user found in violation may have their company banned from using AdSense.
This is a no brainer as any digital marketer worth their weight should not even consider anything as devious as pop-under.