Fake news is an age-old phenomenon, widely assumed to be associated with political propaganda published to sway public opinion. Yet, with the growth of social media, it has become a lucrative business for Web publishers. Despite many studies performed and countermeasures proposed, unreliable news sites have increased in the last years their share of engagement among the top performing news sources. Stifling fake news impact depends on our efforts in limiting the (economic) incentives of fake news producers. In this paper, we aim at enhancing the transparency around these exact incentives, and explore: Who supports the existence of fake news websites via paid ads, either as an advertiser or an ad seller? Who owns these websites and what other Web business are they into? We are the first to systematize the auditing process of fake news revenue flows. We identify the companies that advertise in fake news websites and the intermediary companies responsible for facilitating those ad revenues. We study more than 2,400 popular news websites and show that well-known ad networks, such as Google and IndexExchange, have a direct advertising relation with more than 40% of fake news websites. Using a graph clustering approach on 114.5K sites, we show that entities who own fake news sites, also operate other types of websites pointing to the fact that owning a fake news website is part of a broader business operation.

12 pages, The Web Conference 2023