Samantha Murphy Kelly, writing for Mashable:
Major League Baseball is launching a major initiative to make attending games at stadiums a completely interactive experience for fans.
Taking advantage of Apple's iBeacon indoor mapping, a new feature in iOS 7, the MLB plans to customize its At the Ballpark app for everyone that walks into any of its stadiums nationwide.
"We've been looking at customizing the app based on where you are within the stadium, but GPS is notorious for not working indoors, especially when you are in a building made of steel," Marc Abramson, iOS developer for MLB, told Mashable. "Instead, we are incorporating Apple's new Bluetooth and iBeacon technologies for iOS 7 and couldn't be more excited about the potential."
This sounds very cool. Kelly writes that MLB has been working closely with Apple on this project.
For more on iBeacon, see Michael E. Cohen's piece on it for TidBITS.