People have long been talking about MAC address tracking, the technique malware and marketers use to build a picture of where your device goes and the networks you log into.

At the core of such tracking is the MAC address, a unique identification number tied to each device. Devices looking for a Wi-Fi network send out their MAC address to identify themselves. Wireless routers receive the signals—and addresses—even if a connection is never made. Companies like Euclid or its peer Turnstyle Solutions use the data to track footfall in stores, how people move about in shops, how long they linger in certain sections, and how often they return. Store-owners use the information to target shoppers with offers (paywall) or to move high-value items to highly-trafficked parts of the shop, among other things.

Even though stores may not mine this data to try to identify individuals, there are plenty of legitimate privacy concerns about the data collection, especially since people tend to be unaware that it is happening. Apple’s solution, as discovered by a Swiss programmer, is for iOS 8, the new operating system for iPhones which will be out later this year, to generate a random MAC addresses while scanning for networks. That means that companies and agencies that collect such information will not necessarily know when the same device (i.e., person) visits a store twice, or that the same device pops up in stores across the country or the world, suggesting a much-travelled owner.

Fascinating. Big implications, too, for the industry that’s been built around MAC address tracking.