Without social network context (you are much more likely to meet a friend of a friend than someone living in a country half way around the world), that is impos

Without social network context (you are much more likely to meet a friend of a friend than someone living in a country half way around the world), that is impossible with current-day research. I'd argue that given facebook's dataset of low-resolution photos in crappy lighting conditions, it could actually be 100% impossible. That is, amongst 800 million people, there are bound to be people who look exactly the same as me with available data.