How Facebook Figures Out Everyone You’ve Ever Met
In real life, in the natural course of conversation, it is not uncommon to talk about a person you may know. You meet someone and say, “I’m from Sarasota,” and they say, “Oh, I have a grandparent in Sarasota,” and they tell you where they live and their name, and you may or may not recognize them.
Facebook's reach is insanely creepy. Among the things outlined in this article is the fact that even if YOU never upload your work email address or provide your phone number Facebook still has it. Because someone else did and they've tied it to you.