Bruce Schneier flags a new study in which computer science researchers traced “anonymized” data from social sites back to the real people it is associated with. Interestingly they identify people not through the content that they post but rather through the social graph — they figure out who people are based on who their friends are and who their friends’ friends are.

The researchers are the same ones published a paper last year about de-anonymizing some of the data in the Netflix Prize dataset using a different approach.