Asymmetric Content Moderation in Search Markets: The Case of Adult Websites

We study how a large platform’s unilateral content moderation decisions reshape demand and competition in attention markets. We exploit a large-scale content moderation episode in the adult-content industry: in December 2020, following New York Times reporting and the subsequent suspension of payment services by Visa and MasterCard, MindGeek (owner of Pornhub) abruptly removed roughly 80% of its library—all non-verified uploads—from a catalog of about 13.7 million videos. Using a difference-in-differences design and web-traffic data, we document a 43–48% decline in visits to MindGeek domains immediately after the intervention. Demand does not shift to large competitors in proportion to MindGeek’s losses. Instead, traffic also reallocates toward unmoderated fringe sites, which experience persistent gains (up to 56–58% over the subsequent six months), and toward intermediaries: search engines and link-aggregator websites that actively reroute displaced users toward fringe sites. These findings highlight an externality of unilateral moderation, which can help unmoderated players to emerge, particularly when some users value non-verified content and search frictions are limited.