How Facebook Figures Out Everyone You've Ever Met
by Kashmir Hill on Gizmodo, shared by Tom Ley to Dead from Deadspin > Sports News Without Fear, Favor or Compromise on (#37927)
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.