According to Mac Rumors, "major league baseball Major League Baseball will begin rolling out thousands of iBeacons in ballparks around the country"
They go on to say MLB hopes to have 20 ballparks iBeacon enabled by opening day.
For those not familar with iBeacon, it's a location-based technology service that uses a low power version of Bluetooth (Bluetooth LE) that enables smartphones, smart objects and other computing devices to communicate when in relatively close proximity - within a retail store, for example.
Apple is the driver behind iBeacon, but many other companies are supporting Bluetooth LE.
Baseball will use iBeacon to connect to their existing At the Ballpark mobile app. While exact functionality is yet to be determined, Mac Rumors says:
Functionality will vary by ballpark, with individual teams having significant input and control over what users will see. There are a number of potential use cases including point of interest information, concessions, loyalty and rewards programs, shopping, and more.
This is another example of why you should know about iBeacon and Bluetooth LE.