Quoted from PinMonk:
If you are in data security/cyber security and don't understand the problems with facebook, Giuliani's cyber firm has a position for you.
Facebook is TREMENDOUSLY bad. They use facial recognition to build profiles of people in pictures you post even if they don't have an account. They recently were caught abusing bluetooth to build profiles of phones in the proximity of people's cell phones that had the app installed, abain building profiles of people with no facebook account that made the mistake of leaving their bluetooth open. There are TONS of facebook abuse stories like this. No one should be using them, and yet, they're everywhere.
Stopping Facebook from doing that would be like picking fly shit out of the pepper. It's not like that kind of data mining stops if Facebook goes away.
Every thing you do, regardless of what it is, from walking down the street to talking to friends in person is you broadcasting data. From those direct actions, there is untold amounts of dark data created. Being able to capture and act on that dark data is what the industry has become, and it's not going to slow down. Our technology in machine learning is still so juvenile, yet can already provide insights into these massive datasets that our monkey brains can't even begin to parse.
Besides, what you are talking about isn't really cyber security. It's defining the line of what is private and what is not. It's also basic knowledge that people should be equipped with in 2020. To live a life where you aren't being picked up in dark data, you'd have to exist in a hole in the woods and never go near another human again.
Another example... as you wander around a city, there are numerous devices tracking your phone. You mentioned bluetooth, but think about the wifi on your phone. Do you turn that off when you leave the house? If not, as your phone scans for wifi networks, it's broadcasting identifiers unique to that hardware. That data eventually makes it to some large services that contribute to your overall imprint. That's something you can't do anything about other than turn all broadcasts from your phone off. You are putting that information out there and someone is making use of it.
That's just one example. If you think Facebook using bluetooth or facial recognition to identify people is TREMENDOUSLY bad, you'd have a brain explosion like in the movie Scanners if you knew the reality of it. I'd also like to introduce you to your driver's license, the original facial recognition database.