I started playing around with Foursquare to see what all the fuss was about with those “hey look at me I’m at the grocery store” apps. On itself Foursquare turns this whole thing into a little game where you earn points and merit badges for exploring new and exciting places, which stimulates you to explore even more new and exciting places. It’s fun.
What I learned additionally while playing around with it, is that even without the GPS active on the phone, or the WiFi-localization mode which exists on any Android & iPhone device, Foursquare could figure out where I was pretty damn accurately.
So how does it do this?
Android for example can determine a phone’s location by using GPS, WiFi and cell-tower signals. So while some applications don’t work well without a GPS signal, it’s not really required to get a (not so accurate) fix on your location. So all any app really needs is an internet connection, your cellphone network data and possible some WiFi network info to get a pretty darn accurate idea where you are. Without even using the GPS function on your phone. Interesting.
This isn’t something shocking and new, but it is something to keep in mind when you’re installing random apps on your phone. These apps only need internet access to send your approximate location to whoever wants to know. No other security restrictions required.
EFF posted this interesting article about what cell-phone companies can do with the location data they collect from your phone. But with the advent of the smartphone, anyone who writes an app might be doing the same.