Popup

A Popup is a type of advertisement that is shown off the page that it is generated from. There are basically 2 types of popups, a popup that appears hovering over a browser, and another type called a popunder which appears underneath the browser window. These forms of advertisements are considered a nuisance by many web surfers, which has spawned the development of popup blocker software that is both built in to many web browsers, as well as sold as separate applications. Popups are usually large format advertisements.