In Gary Shteyngart’s 2010 novel, “Super Sad True Love Story,” characters carry around smart devices called äppäräts, which are something like iPhones on meth. The book is set in the near future. Staten Island is the new Brooklyn, and all the characters use their äppäräts to chat and shop and beam their lives out to the world, nonstop. Äppäräts are also equipped with a program called RateMe Plus, which constantly calculates (and broadcasts, of course) a status ranking based on users’ jobs, financials and online popularity, which is gauged by the quantity and quality of what they share. Live-streaming the most intimate details of your life is the only way to get ahead — job promotions and romantic prospects depend on it.

Shteyngart’s extrapolations from first-generation social media are beginning to prove surprisingly prescient. The biggest companies are now slaving away to bring his vision ever closer to real­ity. It’s not a philosophical or ideological statement on their part; it’s just that their business model is predicated on sharing, and finding new ways to extricate more and more from us. This spring, Facebook introduced its 1.7 billion users to a new feature called Live, which allows anyone to broadcast his or her life in a real-time stream to friends and family. The company also said it would prioritize personal posts like Live over those from brands or news organizations — a sign that, like Shteyngart, it thinks people are far more invested in voyeurism than in anything else. (And in theory, it should know.) In August, Instagram, which is owned by Facebook, followed suit with a feature called Stories, allowing users to post photos and videos that disappear after 24 hours. The company described it as a way to “share all the moments of your day, not just the ones you want to keep.”

It all feels like harmless fun, but our online lifestyles have begun to make a real impact in our offline worlds, a trend that doesn’t seem to be reversing. In 2014, Facebook talked with lenders about the possibility of linking profiles to credit scores, and one recent survey showed that 40 percent of college-admission officers now say they peruse applicants’ social-media profiles in addition to evaluating G.P.A.s and essays.