Google has reportedly paid the makers of Adblock Plus, the single most popular browser extension on Chrome and Firefox, to look the other way when it comes to its web advertisements. According to the German news site Horizont, Google and other unnamed companies are paying to be included on a "whitelist" that prevents some of their ads from being blocked by the free service.

Horizont said in a report that it's unclear how much Google has paid Eyeo, the company behind Adblock Plus, to whitelist its ads, and that it doesn't know which other companies are doing the same. Both Eyeo and Google didn't respond to email requests for comment on Friday afternoon — but if we hear back, we'll update this post. In an FAQ page on the Adblock Plus website, Eyeo notes that it offers whitelisting under its Acceptable Ads initiative for free to smaller websites. The Acceptable Ads whitelist, which has been in place since at least 2011, argues that unobtrusive ads should remain viewable as long as they aren't annoying.

Eyeo also argues that it has a reason for charging others for the special treatment. "Managing this list requires significant effort on our side and this task cannot be completely taken over by volunteers," the FAQ says. "That's why we are being paid by some larger properties that serve nonintrusive advertisements."