Kashmir Hill

Rebecca Porter and I were strangers, as far as I knew. Facebook, however, thought we might be connected. Her name popped up this summer on my list of “People You May Know,” the social network’s roster of potential new online friends for me.
 
 The People You May Know feature is notorious for its uncanny ability to recognize who you associate with in real life. It has mystified and disconcerted Facebook users by showing them an old boss, a one-night-stand, or someone they just ran into on the street.