Coarse-grain location data becomes very revealing when you have enough timestamped data points. The NSA's CO-TRAVELER[1] program only needs to watch which tower

Coarse-grain location data becomes very revealing when you have enough timestamped data points. The NSA's CO-TRAVELER[1] program only needs to watch which towers cell phones use to build a very accurate map of each phone's pattern-of-life (where does a phone regularly travel/idle) and social interaction network (e.g. which phones travel/idle together). [1] https://www.washingtonpost.com/apps/g/page/world/how-the-nsa-is-tracking-people-right-now/634/ https://www.washingtonpost.com/apps/g/page/world/how-the-nsa...