Congressmen Edward Markey (Massachusetts) and Joe Barton (Texas) recently asked the four major US wireless carriers (AT&T, Verizon, Sprint, and T-Mobile) about data collection, storage, and disclosure practices for customers' personally identifiable information. All four have since responded, and their letters can be accessed at

The most interesting response is Verizon Wireless' 17-page letter (PDF). It reveals that Verizon plans to soon put a removable sticker on the display of new handsets that warns the user the device may be used to track their location. A sample sticker was provided and here's what it said:

This device is capable of determining its (and your) physical and geographical location and can associate this location data with other customer information. To limit access to location information by others, refer to the user guide for Location settings and be cautious when downloading, accessing, or using applications and services.

Verizon did not detail when the stickers might begin to appear. The company did reveal, however, that it retains user data (including location details) for seven years. Verizon implied that only law enforcement can request access to that information, and that it is not provided or sold to other parties.

The label likely won't actually stop consumers from buying and using smartphones. It will, however, educate them and possibly make them think twice about what information they are broadcasting without deliberately choosing to.

The news follows the discovery that iOS and Android both cache your position, typically determined by cell-tower triangulation, either triggered by traveling between cells or activity on the device itself. This has prompted investigations by regulators in France, Germany, Italy, and South Korea. Interestingly though, this Verizon label is actually in response to a New York Times that raised concerns about how carriers collect and store personal location data, not the recent location caching fiasco.