Even if you don't use it. You may have deleted your Facebook account or perhaps even never created one. But the company may not even need that to have happened to know essential things about you already. How? Through the other many apps it owns (WhatsApp, Instagram, among many), or simply the ones that advertise via them. The company claims those practices are "commonplace in the industry" and that they have "provided more transparency and control to help people manage their data over the years." But for Geoffrey A. Fowler, it isn't enough. Here, he comments on the growing yet invisible dangers of Big Tech monopolies.