Can Facebook use AI to fight online abuse?

Facebook has released statistics on abusive behavior on its social media network, deleting more than 22 million posts for violating its rules against pornography and hate speech – and deleting or adding warnings about violence to another 3.5 million posts. Many of those were detected by automated systems monitoring users' activity, in line with CEO Mark Zuckerberg's statement to Congress that his company would use artificial intelligence to identify social media posts that might violate the company's policies. As an academic researching AI and adversarial machine learning, I can say he was right to acknowledge the significant challenges: "Determining if something is hate speech is very linguistically nuanced." The task of detecting abusive posts and comments on social media is not entirely technological. Even Facebook's human moderators have trouble defining hate speech, inconsistently applying the company's guidelines and even reversing their decisions (especially when they make headlines).