I’ve said cell phones are the best spy devices we’ve ever decided to voluntarily carry around and, as Bruce Schneier points out, the ability to judge a person’s location based on their cellphone signal isn’t restricted only to government agents:
Online retailers have long gathered behavioral metrics about how customers shop, tracking their movements through e-shopping pages and using data to make targeted offers based on user profiles. Retailers in meat-space have had tried to replicate that with frequent shopper offers, store credit cards, and other ways to get shoppers to voluntarily give up data on their behavior, but these efforts have lacked the sort of data capacity provided by anonymous store browsers—at least until now. This holiday season, shopping malls in the US have started collecting data about shoppers by tracking the closest thing to “cookies” human beings carry—their cell phones.
The technology, from Portsmouth, England based Path Intelligence, is called Footpath. It uses monitoring units distributed throughout a mall or retail environment to sense the movement of customers by triangulation, using the strength of their cell phone signals. That data is collected and run through analytics by Path, and provided back to retailers through a secure website.
The location of any device that emits a wireless signal can be triangulated. Again I will state that cell phones are immensely useful but not only to their owners. Combining the fact that cell phones are almost always on their owner, contain a vast amount of personal information about their owner, and have built-in cameras and microphones makes for devices that are great for spying on select individuals. While people can harp on the malls for implementing this technology ultimately it’s nothing new as your cell phone provider, whom I worry about far more, have the exact same information at all times (usually with some history of your past locations).