How did harmful content and misinformation online get so bad — after so much time, money, and scores of people trying to limit the spread of inaccurate, violent, obscene, and harmful content? For starters, the problem is much bigger than it used to be, and human-driven efforts cannot keep up. Even with tens of thousands tackling the problem (Meta’s Trust & Safety team has swelled to an army of more than 40,000) the sheer amount of digital content is too overwhelming. Moderating this content by human review is not only time-consuming, ineffective, and error-prone, it also can endanger the mental...