KASHMIR HILL:

Oh yeah exactly. So they probably know every e-mail address you've ever use for any job you've ever had. You know that e-mail address that you had in college. Every phone number that you've ever had you know probably the landline that you had as a kid. This is all layered onto your layered onto your account. And so this is why I originally became really interested in this concept because of people being so disturbed by their friend recommendations. Really creepy anecdotes from people like a psychiatrist whose patients were being recommended to each other they're a sex worker who was seeing her clients appear there. Even though she had you know communicated with them through a burner phone number and an e-mail address that she never used anywhere else as I was trying to figure out you know how it is that Facebook was so accurately able to make these predictions about who people knew and it what it boiled down to was the shadow contact information. If you have all the contact information that anybody has ever used and you're able to see into the contact books of millions of users you can just make connections between between people that are really incredible and really creepy like you basically know everybody in the world who has ever talked to anyone else in the world through an electronic means.