Late last year, Apple outfitted 254 of its US stores with small, low-power Bluetooth transmitters. Called iBeacons, the transmitters work in tandem with iPhones running iOS 7 and the Apple Store's dedicated app to provide users with very precise location information and guides to getting the most of their shopping trip. Now a company called inMarket is the bringing the technology to provide a group of US grocery store customers with deals, reminders, and rewards.

From today, selected Safeway and Giant Eagle stores in Cleveland, San Francisco, and Seattle will be outfitted with iBeacons that use inMarket's Mobile to Mortar platform to push notifications to customers who have downloaded the company's apps. The apps — such as CheckPoints and List Ease — will receive notifications from the beacons from a set distance. Those notifications can inform the customer of helpful information: an in-store deal on a planned purchase, for example, or a valid coupon for something on a user's wishlist.

The number of stores using inMarket's iBeacons will increase to 150 in the coming weeks, and will reportedly rise to thousands — both "grocery and other types," according to the Associated Press — by the end of 2014. By targeting your phone, the marketing method sounds intrusive, but the iBeacons won't interact with your iOS 7 iPhone unless you're one of the 20 million people that has one of the relevant apps installed.