All that has changed in the past decade. In the same way that electricity went from a luxury enjoyed by the American élite to something just about everyone had, so, too, has fame, or at least being known by strangers, gone from a novelty to a core human experience. The Western intellectual tradition spent millennia maintaining a conceptual boundary between public and private—embedding it in law and politics, norms and etiquette, theorizing and reinscribing it. With the help of a few tech firms, we basically tore it down in about a decade.