ITHACA, N.Y. – Comparing the locations of photos posted on the Internet with social network contacts, Cornell University computer scientists have found that as few as three "co-locations" for images at different times and places could predict with high probability that two people posting photos were socially connected.
The results have implications for online privacy, the researchers said, but also suggest a quantitative answer to a very old psychological question: What can we conclude from observing coincidences?