Apple has begun using iBeacons in 254 US stores, meaning the company can now send direct and personalised notifications to your iPhone about products, events, etc, whenever you visit an Apple Store.
To make use of the iBeacons, you will need an iPhone with iOS 7. You'll also need to download the Apple Store app, then enable Bluetooth, and give Apple permission to track you. This combination allows Apple to study your shopping habits/wants/needs then send tailored notifications to you.
iBeacons is a brand name created by Apple for a specific technology in iOS 7 that allows mobile apps to recognise when an iPhone is near a small wireless sensor called a beacon (or iBeacons, as well). The beacon can transmit data to an iPhone - and visa versa - using Bluetooth Low Energy.
Let's now put this into a scenario: say you own an iPhone 5 and you're walking by an Apple Store equipped with iBeacons. Upon entering a beacon's zone, such as an iPhone table, the beacon will transmit related promotions, coupons and recommendations about iPhones to your iPhone 5 via the Apple Store app.
According to the Associated Press, Apple began using iBeacons in US stores on 6 December and could potentially use the technology to recommend - for instance - that you upgrade from an iPhone 5 to the newer iPhone 5S. Apple's iBeacons will also accept payments, so you can pay for some items using your phone or even request customer service and reserve products.
An iBeacons' range is up to 50 meters, so you may also receive notifications when just walking by an Apple Store. The Apple Store app will simply go into an "in-store mode" and begin sending you tailored alerts.