Protecting your wireless identity
When a smartphone looks for a wireless network to connect to, it will repeatedly broadcast small amounts of information including a unique identification number known as a MAC address.
Some businesses use software to listen for MAC addresses to monitor customer behaviour in real-time.
But for those who want to keep their wi-fi switched on and opt-out of this monitoring, start-up company The Wireless Registry might have the answer.
BBC Click's Jen Copestake finds out more.