19. Pop-ups and Pop-unders

19. Pop-ups and Pop-unders
Pop-ups are a common yet annoying form of advertising on the Internet. If you are just trying to make a much money as possible from your website, you could experiment with them.
If you are trying to grow the traffic and generate loyal visitors, however, you probably should stay away from them. Just consider the hundreds of pop-up blockers out there: there is a reason why they are so popular.
Ad networks that use pop-ups:
Tribal Fusion
PayPopup
PopupAd
Adversal