It seems iOS 9 ad blocker, Crystal, will allow some ads to go through for a fee. From an article on the Wall Street Journal:
Mr. Murphy said he has taken Eyeo up on its offer, and plans to implement an option within his app whereby “acceptable” ads will be displayed to users. The feature will be switched on by default, Mr. Murphy said, and he will receive a flat monthly fee from Eyeo in return. Mr. Murphy declined to disclose the fee, but said he expects to make less money from Eyeo’s payments than from sales of the app itself.
And just like that, Crystal was uninstalled from my devices, to never come back again. Anyone who asks me for recommendations will get others recommended, but Crystal. Conflict of interest like these are unacceptable.
Eyeo, by the way, is the company behind Adblock Plus, which is already accepting payments from “around 70 companies in exchange for letting their ads through its filter” (WSJ). Keep away from that one too!