Jacob Silverman is a critic and freelance journalist who has covered social networks and surveillance for many top newspapers and magazines. He is very anxious about the ease with which Google, Facebook, and Twitter have convinced people to hand over private data to corporations without batting an eyelash.

People who are hooked on social media seem to find it a welcoming home away from home where they can share concerns, memes, quotations, stories, and pictures with relatives, friends from high school, college, work colleagues, and new acquaintances. In the digital playhouse, we share jokes, passions, political propaganda, and what happened to us this morning before we left for work.

Those who are willing to pay any price for this pleasure agree with Sheryl Sandberg, the CEO of Facebook: "People will share more and more of their lives online, transforming relationships on every level — personal, commercial, and institutional."

Silverman is troubled by the public's unwillingness to see that Google+, Facebook, Twitter, Pinterest, and other social media accounts are mining our personal data to increase their advertising revenue. As the author notes: "By clicking like or favorite, or retweeting a promoted tweet, a user becomes a vector in the spreading of advertising. You are selling both a product and your networked persona; in many way, you are the product, particularly when it's your data being sold to advertisers and other unknown partners."

What is feeding this tradeoff? The author surmises:

"Social surveillance allows us to feel as if we have an audience at any time, waiting to be summoned. . . . Social surveillance fulfills our hunger to see and be seen. It offers a finishing school for the self, in which our public performances complete and complement our private identity construction."

Terms of Service charts the shadow side of connections in our quickly changing digital world.