The basic premise of any AI-driven social media feed is that you don’t need to tell it what you want to see. Just by observing what you like, share, comment on, or simply linger over, the algorithm learns what kind of material catches your interest and keeps you on the platform. That’s why the company’s latest announcement to expand a trial to reduce the amount of political content shown to a subset of users is such a big deal. It marks perhaps the most explicit recognition that what people engage with is not always synonymous with...