SimilarWeb data shows visits to Tumblr have fallen nearly 30%, from 521M in Dec. to 370M in Feb., since permanently banning adult content from the site in Dec.
Tumblr has lost 30 percent of web traffic since December — Since Tumblr announced its porn ban in December …
Context & Ripple Effects
Tumblr's December decision to permanently ban adult content was the endpoint of a pressure sequence: an audit found child porn images slipping through detection tools, which got the app pulled from the App Store before it reappeared on the App Store ten days after the ban was announced. The SimilarWeb numbers are the first hard read on what that trade-off cost.
The counterweight in the coverage: five years later Tumblr reported a 349.55% surge in users after the X ban in Brazil, showing the same audience can flood back in when a rival platform restricts access instead.
First-order effects
- Tumblr's monthly web visits fell from 521M in December to 370M in February per SimilarWeb — roughly 151M visits gone within two months of the ban taking effect on December 17.
- Adult-content creators and their audiences, a core segment of the site, lost their publishing home overnight and began leaving the platform.
Second-order effects
- Platforms willing to host adult content become the natural landing spot for Tumblr's displaced creators and traffic, converting Tumblr's moderation decision into a competitor acquisition channel.
- The traffic collapse pressures Tumblr's advertising pitch — fewer visits means less inventory — while the App Store episode showed Apple can force the policy either way.
Third-order effects
- Content policy at consumer platforms is effectively set by distribution gatekeepers (app stores, payment providers) rather than by what audiences want, with traffic data like SimilarWeb's becoming the public scorecard for those trade-offs.
- Audience flows between platforms are event-driven: bans push users out, rival bans pull them in, so a platform's size reflects other companies' moderation decisions as much as its own product.
The trend: Platform moderation is increasingly dictated by app-store and payment gatekeepers, and audience volume now swings on other platforms' bans as much as on a site's own choices.