Google announced that their AdSense product has updated their ad policies to disallow Google AdSense ads from showing on pages that are triggered by pop up or pop under techniques. In addition, you can not use Google AdSense ads on any web site that deploys pop under ads.

Google wrote:

Here are the new policies:

Publishers are not permitted to place Google ads on sites which have more than three pop-ups. If pop-ups are displayed on a site, they may not interfere with site navigation, change user preferences, initiate downloads, or distribute viruses.
Publishers are not permitted to place Google ads on sites that contain or trigger pop-unders.
Additionally, sites using AdSense may not be loaded by any software that triggers pop-ups, modifies browser settings, redirects users to unwanted sites, or otherwise interferes with normal site navigation. It is your responsibility to ensure that no ad network or affiliates use such methods to direct traffic to pages that contain your AdSense code.

It is about time Google AdSense draws a line in the sand here.

Forum discussion at Google+.