Ad networks doesn't pay for white listing! The article is little confusing (typical for German press). Certain ads on certain websites can get into the white list. So if somebody pays it is the company running the website. And smaller websites like Reddit got their ads even white listed for free. See my reply to Karunamon [1].

However the comment you replied to was about the accusation that Adblock Plus would be dishonest, which just isn't true.

[1] https://news.ycombinator.com/item?id=5996565