“Content algorithms would continue to drive us down rabbit holes toward extremism and conspiracy theories, since automating recommendations is cheaper than paying human editors to decide what’s worth our time. And radical content, incubated in insular online communities, would continue to inspire mass shootings. By influencing two billion brains in these ways, today’s social media holds the pen of world history: The forces it has unleashed will affect future elections and even our ability to tell fact from fiction, increasing the divisions within society.”