Even though Facebook by itself doesn't seem to provide much value anymore, it's incredible how much of a platform lock-in the have. For example, Facebook login becoming essentially a universal identity provider. The worst thing is even when you create a new account under a different name they still manage to track you down, and start suggesting adding friends from the old account. I wonder how they do this, by tracki…
It's interesting how identifiable you are just by compounding information provided by the browser: https://amiunique.org/fp Browser fingerprint plus IP and/or geo location and I'd think you could get a fairly accurate guess of who you are.
There is a JS project based on that and that gives you an ID based on the fingerprint. [1]
[1] https://github.com/Valve/fingerprintjs2
Edit: I just saw that the link provide even more data like this. Just my list of font is a > 99.9% of uniqueness. Multiplied by all the other likelihood, it's getting close to having the signature of every person on internet.