Greetings! With the recent post on iBeacon's implementation in MLB parks, I wanted to chime in with a little more information regarding how the technology behind the magic works, what it's for, what it will do for you, and what it does not do.
iBeacon is generally described as an indoor location/positioning system. It makes use of profiles in the Bluetooth LE/BLE/Bluetooth Smart protocol and it's part of the Bluetooth 4.0 specification. I guess you can say they're having a branding problem.
It works like this: The Padres are going to place iBeacon transmitters around the park, the most obvious place for this will be the Padres Store. The transmitters identify themselves to your device with a UUID (Universal Unique Identifier), a major integer, and a minor integer. Basically they will beam out to your device in computer talk saying, "Hello, I am an MLB iBeacon transmitter (the UUID), I am in Petco Park (the major integer), and I am in the Padres Store (the minor integer)." From there, the data they'll send has to go somewhere to be handled correctly, and I'm assuming MLB is going to make use of the MLB At the Ballpark app they had us install at FanFest to deliver notifications. From what I've read, you're going to need to go into the app to enable this. It won't work until you do. The app has its own UUID and knows what transmitter UUIDs to look for, but it must be told to do so. Once you've given permission, it will be able to launch the app in the background to let you know you're in range of an iBeacon and it has something to show you when you turn on your screen. That seems to be the most magical aspect of this, that apps will open by themselves and be ready for you when you look at your device - with your permission, of course.
With Bluetooth's range, we're looking at a maximum range of 50 meters, but with brick and steel in the way, we're looking at much less than that with any true reliability. I'll guess it's about twenty yards in the real world. The accuracy is kind of fuzzy in telling where exactly you are as the proximity can only determine four levels of location. It can determine if you're on top of it, near to it, far from it, or if the location is unknown.
The most obvious job to be done by iBeacon so far has been laid out in the hypothetical applications they've already talked about: letting customers know about the sales, offers, or promotions available in whatever area you happen to be. I'm guessing they'll initially use this to let you know what the deal of the home stand is.
I'm not particularly interested in the delivery of ads other than for picking up a fairly priced t-shirt, but something I'd like to see them do with iBeacon is to deploy it in the Padres Museum That They're Definitely Putting In The Showley Bros. Candy Factory, Right Padres? A self-guided tour app that pops up relevant facts or links to other media like audio/video about the exhibit you're standing in front of would be a useful and impressive implementation.
If you want to opt out of the whole thing, you can turn Bluetooth off on your device. You should be able to find more granular settings to allow/disallow access for individual apps in the Settings (or equivalent) section of your device, or even within the app itself. There's nothing in the specification that grants access to any data you haven't given the app access to and iBeacon transmitters are designed only to send information to you, not to receive any information, nor to send information between iBeacon receiver devices. To receive information from you, they'll have to use iBeacon to direct you to a secondary service that supports this function. Plus, if they really wanted more personal information from you, they'd probably just trade it for an entry to a raffle where you could win a stay in a timeshare or give you a credit card in exchange for a crappy hat.
I haven't done any real-world testing with an iBeacon yet, but I'll do my best to answer any further questions below.