I know that I have probably not clicked on one since 1996, yet there are still tons of sites that continue to use them and even abuse them like annoyed visitors are good for business. Are there specific niches that they work on or a certain demographic?
many browsers now contain pop up blockers, which specifically stop the pop up scripts from running and the advertising window appearing, unless the user gives their explicit consent.
I use an ad blocker to stop pop ups/unders appearing, I think they are so annoying. As for advertising, well I am not sure, just give it a go and see what happens.
Yes, they still work for certain demographics. If you are buying Pay-Per-View (ppv) traffic, it is usually a pop up/under or an interstitial (the click here to continue to the content page you sometimes see). The people who install free toolbars and/or who really like sweepstakes are generally your target demographic. I wouldn't serve popups from a site I owned though. Most browsers block them these days.
browsers these days have pop up blockers. people also use adware tools to block such ads, in order to make a few bucks with pop up/under ads, you will need to have a lot of traffic. its just the number game. more visitors you have more like you will have someone to click on them.
Unless you are using a traffic source like PPV (Pay Per View) i think thats the only effective way to use pop ups for adveritisng. just my opinion