Popup Ad Filter works at a low level in the Internet Explorer engine - stopping a potential ad in it's tracks before it even has time to download. This prevents popup and pop-under ads from stealing bandwidth from your other legitimate downloads. Further more, there is no chance for the popup ads to place any cookie on your system. Unlike most pop-up killers, there's no need to designate particular websites or keywords - it works without human intervention; and there's no need of additional options when you open a new window - it only blocks unsolicited pop-up windows while does not in any way interfere with opening new windows.