Definition: A pop-up ad is an online advertisement that displays in a new Web browser window; hence the "pop-up" designation. The advertisement manifests in front of the present browser window, and usually can be dismissed by clicking "close" or "cancel"; however, some pop-up ads are particularly intrusive and can call up even more advertisements.
Pop-under ads are similar to pop-up advertisements; these ads are displayed behind the main Web browser window instead of in front.
Many websites use pop-up technology in useful, legitimate ways: forms, multimedia, additional data, etc. It's up to the user whether or not pop-ups should be blocked universally for all Web sites.
How to deal with pop-ups
If you're not a fan of pop-up advertisements, you do have options:
Also Known As: banner ads, floating ads
