You only need to know which cell towers the phones are traveling past[1], and you get a nice relationship map (and movement data). I'm sure a similar analysis c

You only need to know which cell towers the phones are traveling past[1], and you get a nice relationship map (and movement data). I'm sure a similar analysis can be done with IP headers. [1] http://apps.washingtonpost.com/g/page/national/how-the-nsa-is-tracking-people-right-now/634/ http://apps.washingtonpost.com/g/page/national/how-the-nsa-i...