[klyrs]

> I don’t have Facebook and have zero interactions with ANY of their products in my life.

Maybe. But if any of your friends/family is on Facebook, they may have uploaded their contacts, and you quite likely have a "shadow profile" that they're using to track you across the net. You might not know Facebook, but Facebook knows you.

[thentherewere2]

Is that really an issue? Its really a missing data problem. Your data is "missing" and facebook can infer with some probability you exist and the people your "shadow profile" might interact with.

[klyrs]

If six of your contacts have provided them with the same name and email address, then they know with near certainty that those six people have you as a mutual contact. When they spot an ad profile with the same email address, that comes with a dossier on your browsing and shopping habits, which are used to infer your interests etc. It's not a "missing" data problem, it's an embarrassment of data problem.

[filoleg]

That’s pretty much all there is to it, yeah, just a missing data problem. But once you slap the “shadow profile” label on it, it gets “shady” and “scary”. A pretty cool lesson in how to make something fairly trivial and non-threatening seem scary to people.

Note: not currently or in the past employed by Meta or any affiliated companies, so that’s just purely my own take.