A few years ago Apple started iBeacon activations at many of its U.S. Apple retail stores. However, I'm looking forward to seeing it used in the home.
iBeacon is an indoor positioning system that Apple says is a "a new class of low-powered, low-cost transmitters that can notify nearby iOS devices of their presence." The technology enables an iOS device or other hardware to send push notifications to iOS devices within close proximity. In the Apple retail stores, it can do things such as informing you of promotional discounts.
Apple’s iBeacon works on Low Energy Bluetooth (BLE). It can be used in a store — not just an Apple store — in a way that allows iBeacons to beam you personal notifications of items around you that are on sale. What's more, it can enable payments at the point of Sale (POS) such that you don’t need to remove your wallet or card to make a payment.
There are applications beyond the retail sector. Imagine iBeacons in a museum giving your information on the exhibit you're currently looking at.
What of the home? If Apple released the iServe home server I've long wanted, it would be a perfect match for iBeacon services. It could be used for things such as: unlocking the front door as you approach; turning lights on/off as you enter/leave rooms; waking up Macs as you approach them; controlling a/c and heat for rooms that we're in; and providing specific location based reminders or notifications.