Whats the most annoying ad format for you as a surfer? For example popunder (and its varieties like tabunder). It's no secret that this one is the most profitable format for publishers, and users are already used to it, as a their fee for free content. Using popunder on your websites? Or other example - fake download buttons on banners. Even adsense sins with such creatures on websites with free files, such as download.cnet Do you use any ad blocker? How effective is yours?