Facebook removes “pseudoscience” from the list of categories advertisers can use to target people after report that the category contained more than 78M people
While vowing to police COVID-19 misinformation on its platform, Facebook let advertisers target users interested in"pseudoscience"
Context & Ripple Effects
The move caps a rapid sequence of ad-policy reversals: weeks after Facebook banned ads promising COVID-19 cures and temporarily barred medical face-mask listings, The Markup reported that advertisers could still target a "pseudoscience" interest category containing more than 78 million people. Removing the category concedes that the ad-targeting system itself was amplifying health misinformation even as the company policed organic posts.
The episode fits a broader 2020 pattern at Facebook of health-misinformation rules arriving only after outside pressure — a pattern that extended into December, when the company began removing debunked coronavirus-vaccine claims and took down nine Pages flagged by a think tank.
First-order effects
- Advertisers lose access to a ready-made audience of 78M+ users labeled interested in pseudoscience, closing one of the cheapest channels for reaching health-misinformation-susceptible users.
- Facebook's ads team must re-audit adjacent interest categories built from user behavior, since the pseudoscience label was generated by the same inference pipeline as thousands of other targeting segments.
Second-order effects
- Rival platforms face the same question about their own inferred-interest taxonomies, because any ad product that clusters users by fringe interests offers buyers the same workaround Facebook just closed.
- Public-health advertisers and fact-checking groups gain leverage to demand disclosure of how large other sensitive inferred categories are, turning audience-size reporting into an accountability tool.
Third-order effects
- If the pattern holds, platform moderation expands from policing content to policing the advertising infrastructure itself — inferred-audience categories become a regulated surface alongside posts and Pages.
- The recurring sequence of exposé-then-policy-change points toward external audits or regulatory requirements for ad-targeting systems, rather than voluntary category removals, as the end state.
The trend: Platform trust-and-safety is migrating from visible content moderation into the hidden machinery of ad targeting, where each exposed category forces a structural cleanup rather than a one-off takedown.