When white supremacists plan rallies like the one last week in Charlottesville, Virginia, they often organise their events on Facebook, pay for supplies with PayPal, book their lodging with Airbnb and ride with Uber. Technology companies, for their part, have been taking pains to distance themselves from these customers.
But sometimes it takes more than automated systems or complaints from other users to identify and block those who promote hate speech or violence, so companies are finding novel ways to spot and shut down content they deem inappropriate or dangerous.