When your phone downloads stuff, their servers can see your IP. While IPs may not give very specific locations by themselves, the fact that your IP may change a

When your phone downloads stuff, their servers can see your IP. While IPs may not give very specific locations by themselves, the fact that your IP may change as you move around helps a lot to narrow it down. Collect data for a few days to learn schedules, throw in some more specific data purchased from ISPs, other fingerprints, plot it on top of an actual map with roads and buildings, and you’ve got a very good guess of where specific people are, where they live and work, and how they move around. Correlate that with other people’s data and eventually you’ll be able to guess who they live and hang with.