Study: Reddit's 2020 'Great Ban' Cut Toxicity Overall but Radicalized a Minority (2024)

In 2024, researchers Lorenzo Cima, Amaury Trujillo, Marco Avvenuti, and Stefano Cresci published the most rigorous empirical assessment to date of Reddit's June 2020 'Great Ban,' the content-policy purge that removed roughly 2,000 communities including r/The_Donald and r/ChapoTrapHouse. Presented at the ACM Web Science Conference, the study analyzed about 16 million comments posted by some 17,000 affected users over a 14-month window spanning the ban.

The headline findings were mixed. On the efficacy side, 15.6% of affected users abandoned Reddit entirely after their communities were removed, and those who stayed reduced their toxicity by an average of 6.6% — corroborating earlier work suggesting deplatforming lowers aggregate harm. On the unintended-consequences side, roughly 5% of users reacted in the opposite direction, increasing their toxicity by more than 70% of their pre-ban level. The intervention, in other words, calmed the majority while hardening a militant minority.

The result fits a pattern established across the deplatforming literature — including studies of r/The_Donald's migration and of banned users moving to fringe platforms — in which removing a community reduces its overall reach and activity but can push its most committed members toward greater extremity, often on less-moderated sites. It complicates any simple claim that mass bans straightforwardly 'work' or 'fail.'

Because the Great Ban is the single largest moderation action in Reddit's history, the study functions as a scorecard on the platform's central tool for dealing with hate and harassment. Its nuanced verdict — broad harm reduction alongside a real radicalizing tail — bears directly on how Reddit and other platforms should weigh mass deplatforming against the risk of driving their worst users somewhere worse.