Living in the information age and not sharing information at all is like dancing in the rain and not getting wet. The cameras are always on and the gorgon always staring. It might be your friends post, their camera or a corporations.
It's worth considering that privacy wasn't guaranteed in the old days either, save for the laws people created to enabled it. In the past, if a tyrant wanted to find a thief, they'd search every home. This situation is unreasonable to a free people. So folks relied on laws then, as we must now, to ensure that a person's rights are protected.
If a companies tech is capable of tracking a person, selling it or making it available to the public unrestricted would violate their 4th amendment rights. Because government agents could also use the data unrestricted to peer into your life. All without having to break down the door to your home. So while it might be technically possible to know everything about a person in the information age, the right to that information belongs to the individual.
Ahh, but copyright won the last war, by moving to centralised platforms. The privacy mavens are going to lose, but they are going to lose to Big Brother, not to decentralisation.