Finally, and explanation that makes sense!

Basically many app makers do not encrypt the data they transmit over the Internet, for example Google Maps. So if you have the right Internet Access, you can watch everything they do through the information sent back by Apps. With map programs, they are telling you the location of the person. So you don't even need to physically do anything to track a phone, you can just watch the Internet traffic they send back. Wow! And very clever.

How App Developers Leave the Door Open to NSA Surveillance - MIT Technology Review

Labels: privacy, smart phones, spying