Full Article:
https://gizmodo.com/how-facebook-figures-out-everyone-youve-ever-met-1819822691This has been setting in my bookmarks for awhile now, but it is a riveting and concerning read about how Facebook keeps and uses people's information to connect people to each other, even people who aren't Facebook users. The secret sauce is your phone contacts (it can also use email contacts and such on a computer, but phone contacts are real gold). When people start using Facebook, they're invited to upload those contacts to help find their friends...you do so and then you get the portion that's on Facebook, who you can send friend invites to.
But what Facebook doesn't clearly reveal is that they save those contacts and all of the information that goes with it (phone numbers, emails, IMs, nicknames, other social network account names, etc.), which they use to put together a 'shadow profile' of people, even those that don't have Facebook accounts. Even if you haven't shared your contacts with Facebook, if someone has shared yours Facebook will still know of your association and may recommend them to you as someone you may know. Or if two people have uploaded a contact that has the same information (whether that person is on Facebook or not), Facebook will assume that those two people likely have some connection and recommend them to each other. This is how, for example, two patients of the same psychologist were recommended to each other, or how a lawyer's colleague was recommended to him despite only ever giving the person their work email.
And even worse, there's no way to get Facebook to delete this information it has on you short of going to everybody who might have uploaded it and asking them to request that they delete it. And Facebook won't even show what information it's gathered on you in this manner...ironically, supposedly to protect the privacy of the people who uploaded it. In fact, this was only ever discovered thanks to a bug that temporarily showed people the shadow information Facebook had collected on their friends.
It's no secret that I'm not a fan of social media, but this is yet another reason why Facebook is the worst of the worst. This is just another example of how Facebook prioritizes its own growth and profit over the privacy and safety of its users, and a reminder to be very careful about what you give Facebook, cause it'll use anything you give them to their own advantage.
