Aside from networking, companies use ultrasonic signals (or beacons) to gather information about users. That could include monitoring television viewing and web browsing habits, tracking users across multiple devices, or determining a shopper’s precise location within a store.
They use this information to send alerts that are relevant to your surroundings – such as a welcome message when you enter a museum or letting you know about a sale when you pass by a particular store.
But since this technology records sound – even if temporarily – it could constitute a breach of privacy. An analysis of various Australian regulations covering listening devices and surveillance reveals a legal grey area in relation to ultrasonic beacons.