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How are popunder ads different from pop-up ads? Are they any less annoying?
Hope this helps;
Pop-under ads are similar to pop-up ads, but the ad window appears hidden behind the main browser window rather than superimposed in front of it. As pop-up ads became widespread, many users learned to immediately close the popup ads that appeared over a site without looking at them. Pop-under ads do not immediately impede a user's ability to view the site content, and thus usually remain unnoticed until the main browser window is closed, leaving the user's attention free for the advertisement. Although the pop-under ad is ubiquitous with annoying methodologies it still is used by major publishers such as CNN.com and The Wall Street Journal.