An Apple patent (number 20120302256 at the U.S. Patent & Trademark Office shows that the company is working on ways to identify and locate users on a mobile network.
A system and method of locating "friends" having mobile devices connected to a network and associated with a user account is disclosed. The method includes sending a request to a mobile device, the mobile device determining its present geographic location and responding to the requestor with this information. This information may be in the form of a coordinate location such as a GPS location or it may be in the form of a name that the mobile device owner assigned to a particular area (e.g., "home"). Having this location information, a user is able to view the location of the friend that is associated with the mobile device.
Here's Apple's background on the invention: "Mobile devices have been adapted to a wide variety of applications, including computing, communication, and entertainment. Through...| Read more »