3) Even the big sites still provide gateways to radicalism

Experts on white supremacy say that while 8chan might grab headlines, some people — especially young white men — first get a taste of the ideology on popular sites like Twitter and YouTube, despite all the years of pressure for the services to stop fostering hate.

Beirich said tech industry leaders turned a blind eye to white nationalist speech on their sites until the deadly clash between white supremacists and counter-protesters in Charlottesville, Va., in August 2017 that prompted a public reckoning about online hatred.

“Until 2017, for 10 years, we had no idea how many young white men were radicalized into hardcore white nationalism” online, she said. “This is why we’ve been arguing hate groups should come off of these mainstream platforms for years.”

Since then, the companies have taken steps to crack down. Facebook earlier this year expanded its definition of hate speech to include white nationalist and white separatist content. But the move sparked objections from some right-wing commentators, who tied the policy to longstanding allegations that online platforms censor conservative speech. And advocacy groups warned that the policy shift could inadvertently sweep up groups looking to combat online extremism.