Your online privacy is more secure if you are not on Facebook, but every time you go to a webpage and a cookie is put on your computer it is basically doing the same thing. Facebook just perfected it first.
In reality, Facebook, Google, Yahoo, and others know far more about you than the government.
In reality the government cane easily find out anything Facebook, Google, Yahoo, and others know, if they don't already know it themselves.
To quote the bureaucrat Thaddeus Araman in the Asimov story The Dead Past: "You have created a new world among the three of you. I congratulate you. Happy goldfish bowl to you, to me, to everyone, and may each of you fry in hell forever."
Not entirely correct. Facebook collects your browsing history even if you aren't a Facebook user due to their agreements with third parties.
I tested that myself. I installed a barebones Windows and Linux VM on one of my machines. Browsed several websites then looked at the cookies stored on my computer. Guess what? A facebook cookie was on my computer despite NOT using those virtual machines to go to, or browse Facebook at all.
Facebook is everywhere, and that my friend, is the problem.
It used to be that a cookie stored on your computer from a specific website was ONLY readable by that website. Not anymore!