Macy's experiments with location-sensitive shopping have apparently paid off -- in the wake of a successful trial, the retail behemoth has unveiled plans to put iBeacons in all of its stores. Once they're activated this fall, you can get discounts and other promos on your iPhone as you wander through the store; you only need to install the Macy's app and keep Bluetooth turned on. There will only be regular deals at first, but an upgrade in the spring will offer department-specific discounts. You may get a special deal on a coat right as you're swinging by the men's or women's clothing sections, for instance. You're probably not going to go out of your way to shop at Macy's just to see bargains appear on your mobile screen, but this could be a useful perk if you're already a frequent customer.