h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Pop-up's appear on mostly freebie websites that generate revenue from this type of advertising. They will always be in existance until the day that people realize that "free" does have a cost of some type attached. Nobody can afford to give you a free email or webspace, it only makes sense.
pedboy

Not only that. Some people who run 'free' websites *need* the revenue from the pop-up ads. As a case in point, consider http://www.nitpickers.com The site is run by a private individual who wishes to allow free access to the site. He has to pay for website hosting, amongst other things, so he uses pop-up advertising in an attempt to cover his costs. He limits the pop-ups to one per visit, out of consideration to his visitors. Unfortunately, even with as many visitors as he can get, the revenue doesn't come close to break-even, so the poor guy is regularly out of pocket for providing a site that is a lot of fun. (If you like nitpicking films, which I do!)

yes, but it's so easy to block them that whether they exist or not is of no concern.