Remember the advertising scenes from Minority Report?
You might also remember the very creepy Wi-Fi tracker bins that appeared in the City of London in August. Operated by Renew London, they tracked the smartphones that walked past them in the street. The bins had screens on them that could show ads that were theoretically tailored to the people walking past at any moment. 530,000 unique smartphones were tracked before the City pulled the plug on the initial trial over privacy concerns.
The problem here is that your smartphone isn’t connecting to a network and giving over information without your permission – it’s just broadcasting that it’s turned-on. If your Wi-Fi card is actively searching for available networks it has to tell those networks who it is, and that information is a 12-long string of letters and numbers known as a MAC address.
It’s rather like walking around with your house number and postcode written on a note, stuck to your forehead. People won’t know anything about you specifically, but with enough watchers recognising that note going from place to place you can build up a pretty good picture of the kind of person you are. Whether you prefer to shop at Tesco to Sainsbury’s; whether you’re more likely to buy chicken with wine or beef and beer; whether your interests in certain health products might mean you’re pregnant without even realising yet.
There are as many as 40 firms offering tracking services like this to stores that want to see how their customers shop, reports the Washington Post. That means where they go in the store, how long they wait at the tills, which products they cluster around, how often they visit – and which other stores they also visit. Minority Report’s eye scanners are unrealistic in their lack of ambition: they’re way more complicated than they need to be, but also not part of an integrated system.
Online advertising has been shaken up in the wake of the largest browsers introducing ‘Do Not Track’ features. When turned on, they stop adverts from placing cookies on your machine so they can follow you around the web, adjusting what they show you dependent on where you’re looking.
You can’t really do that with a smartphone’s MAC address, but several companies like this do let people enter their MAC addresses into a database manually as a kind of opt-out. It’s time-consuming, and of course it’s not particularly well advertised. Hence the need for the Wireless Registry. Here’s Brian Fung at the Washington Post:
Together with the Future of Privacy Forum, [founders Stillman Bradish and Patrick Parodi] hope to build a kind of central Do Not Call list for MAC addresses. At least in theory, consumers will be able to visit a single Web site, register their MAC addresses for free, and the major tracking companies that have committed to the project will pledge not to follow those addresses around brick-and-mortar stores. It’s a form of potential self-regulation that should look familiar if you’ve been following the debate over online tracking, where Web browsers have begun letting users tell commercial Web sites they don’t wish to be followed.
As a solution it seems a good one, but the flip-side is that it would only take one leak for a very, very valuable list of many unique smartphone identifiers to suddenly be available in the wild. It’s likely that we’ll see more solutions like this being suggested – both from the tech industry and from governments – as offline tracking becomes more of a privacy worry.
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