In short, your emotional swings and insecurities and general behavior patterns are subtly manipulated by social media, all ultimately translating into big data — and, of course, big money — for someone else.

What do social-media users get in return? Sure, there are vacation shots and wedding photos, which are nice. On the flipside, Lanier outlines how social media rewards jerky behavior, encourages mass jerkdom in the larger populace, corrupts journalism (“the more successful a writer is in this system, the less she knows what she’s writing”), corrodes empathy, encourages fakery, deprives arguments of context, distorts reality, spreads unhappiness, and on and on and on. According to a new report from Pew Research, four in ten Americans have “personally experienced online harassment.” If one were to narrow that survey to people who work in politics, you can bet the result would be a lot closer to ten in ten.