Last week Apple rolled out iBeacons throughout their US stores, which was reported heavily by the Mac news sites but they all seemed to miss one major point.
Apple can now track footfall and patterns in their stores.
This will let them gain insight and highlight hotspots, areas of popularity and congestion and ultimately reconfigure or tweak their stores to optimise the experience (sell more). With nearly 400m visitors 1 to their stores in the past year; that's the potential for a lot of data.
Now it's worth noting that iBeacons themselves are entirely passive, the beacon has no idea whether one or 100 iOS devices are in the nearby area. However, as Apple control the Apple Store app that gets woken up whenever one of the registered beacons it listen for enters range they can pipe up the info straight from the users device to the cloud.
Combine that with the customers Apple ID (which the Apple Store app already has) and you know what products they're interested in, what stores they visit and can link this with what they have/do/may purchase.
So whilst on the surface this looks like a way of increasing customer engagement whilst in the store, it may well be an analytical tool for Apple to improve footfall and redesign their stores.