Dot_Media - 10:26 pm on Nov 29, 2011 (gmt 0)
I despise websites that use interstitial ads, popups, locked modals and popunders. find another use for your PDF or don't make them. :/
that being said it would be interesting to see what niche(s) we are talking about. is there value in making something informative/useful and getting links from it? that'd be my best strategy and a sustainable one since google hates anyone making money off of ads besides them.