"What’s a Facebook shadow profile, and should you be worried about it?"
You can thank anyone who allowed Facebook to scan their mobile phone contacts through the “find friends” feature.
When someone uses this feature, Facebook downloads all of a phone’s contact data to its own servers. This includes mostly emails and phone numbers. At the same time, Facebook is also collecting harder-to track data on how you and all your friends and friends of friends are connected to each other. That’s how it finds people to recommend for its “people you may know” feature.
The company’s mobile app even tells you it will do this...
"What’s a Facebook shadow profile, and should you be worried about it?"
You can thank anyone who allowed Facebook to scan their mobile phone contacts through the “find friends” feature. When someone uses this feature, Facebook downloads all of a phone’s contact data to its own servers. This includes mostly emails and phone numbers. At the same time, Facebook is also collecting harder-to track data on how you and all your friends and friends of friends are connected to each other. That’s how it finds people to recommend for its “people you may know” feature.
The company’s mobile app even tells you it will do this...
https://www.dailydot.com/unclick/facebook-shadow-profiles-pr...