I feel like this comment might give a mistaken impression, so I'd like to clarify. Simply rolling out iBeacons does not replicate the copious data that one can

I feel like this comment might give a mistaken impression, so I'd like to clarify. Simply rolling out iBeacons does not replicate the copious data that one can currently get by monitoring WiFi probe requests. iBeacons, as designed, broadcast packets at a set rate using Bluetooth LE, and devices scan for those broadcasts. There is no two-way communication, and no probe requests from client devices. In order for a company to use information from an iBeacon installation, they must have software running on the client scanning for unique iBeacon UUIDs, optionally filtered by "major" and "minor" uint16s to represent separate locations and nodes. Apple limits iOS apps to scanning for 20 UUIDs at any given time. If the user does not have software that in some way scans for and does something with data from a particular iBeacon UUID, then the implementer gets no information. Thus, iBeacons move control over location and identity data from third parties to users. If a user installs, say, a Target iOS app, it can now scan for an iBeacon UUID that Target generates and can roll out across the country. Only once the user has made that affirmative choice can Target acquire information about that user or device.