That doesn't sound accurate to me...
You're not always talking to everybody. On Facebook you can create friend lists, and then post things that are only visible to the people in the chosen list, in the same way that you can share things with only certain "Circles" on Google+. For example, I have different lists for "Close Friends", "Family", "Work Friends", "Random Acquaintances", etc. If I choose, I can share a post with only my "close friends" list, and none of my family or work friends will see it.
This problem has been solved already. On Google+ the concept is called "Circles". On Facebook, they call them "Friends Lists". Why does everyone on HN praise Google+ Circles, but ignore or hate the Facebook Friends Lists feature?