The growing ubiquity of mobile phones and smartphone applications has ushered in an era in which tremendous amounts of user data have become available to the companies that operate and distribute them - sometimes released publicly as "anonymised" or aggregated data sets.The story is based on an article in Nature - Scientific Reports by Yves-Alexandre de Montjoye, César A. Hidalgo, Michel Verleysen & Vincent D. Blondel.:
These data are of extraordinary value to advertisers and service providers, but also for example to those who plan shopping centres, allocate emergency services, and a new generation of social scientists.
We study fifteen months of human mobility data for one and a half million individuals and find that human mobility traces are highly unique. In fact, in a dataset where the location of an individual is specified hourly, and with a spatial resolution equal to that given by the carrier's antennas, four spatio-temporal points are enough to uniquely identify 95% of the individuals. We coarsen the data spatially and temporally to find a formula for the uniqueness of human mobility traces given their resolution and the available outside information. This formula shows that the uniqueness of mobility traces decays approximately as the 1/10 power of their resolution. Hence, even coarse datasets provide little anonymity. These findings represent fundamental constraints to an individual's privacy and have important implications for the design of frameworks and institutions dedicated to protect the privacy of individuals.