How ad services watch you (and what to do about it)
AD SERVICES ARE GATHERING MASSIVE AMOUNTS OF INFORMATION ON YOU. IT’S TIME TO STOP THEM.
IT’S NO REVELATION to note that the amount of information that ad services gather on internet users and mobile phone users is astronomical. Depending on your privacy settings, they can monitor which sites you visit, what mobile apps you use and any ads you might tap on. They can often track your location and movements and get a surprisingly complete picture of all your online activity.
It’s not just the ad companies that can do this. Using the interfaces provided by those ad companies, individuals and companies have the means to track you quite comprehensively. Just this year, a report from the University of Washington called ‘Exploring ADINT: Using Ad Targeting for Surveillance on a Budget’ showed that with just US$1,000 anybody can use targeted ads “to track the locations of targeted individuals as they move from home, to work and to other sensitive locations. We find that we can target ads to users of specific applications and at specific locations.”
It’s scary stuff, and it’s probably time that you took action to stop the ad networks from tracking you.
HOW YOU GET TRACKED
The thing about online advertising is that it’s surprisingly concentrated. While you likely use hundreds or thousands of different websites and mobile apps, those sites and apps commonly rely on a handful of online ad services to deliver ads.
When you visit a website with a banner ad, that site is usually not actually serving up the ad itself. Instead it’s just making space on the page, and then reaching out to a third-party ad server like DoubleClick and asking it to fill that gap with an ad. Suddenly, your PC is communicating with DoubleClick, and the ad service can upload a cookie to your browser. Then you go to a different site. It also has a DoubleClick ad embedded. Having placed a cookie on your computer on the first site, now DoubleClick knows that it’s the same person visiting both sites. As you move about, from site to site with DoubleClick ads embedded, the company can get a pretty complete record of your online movements.
The same applies to mobile ads. The ads embedded in your free mobile apps aren’t built into the app — they’re typically served by one of the major ad networks. Although they can’t upload cookies, they can use a thing called mobile advertising IDs (MAIDs) to individually identify phones to which they’re uploading ads. Your phone gives them a unique identifier, nominally so that they can deliver targeted ads customised to you. That ID, however, can also be used by the ad services to track which apps you’re using and at what times.
HOW TO DEAL WITH AD TRACKING
So how do you stop all this from going on? Start with these steps:
01 DISABLE THIRD-PARTY COOKIES
The first thing to do is turn off third-party cookies in your browser, which prevents embedded ads from uploading cookies to your device. * In Safari, they’re disabled by default. * In Firefox, you have to go to ‘Options > Privacy’ and select ‘Use custom settings for
WHEN YOU VISIT A WEBSITE WITH A BANNER AD, THAT SITE IS USUALLY NOT ACTUALLY SERVING UP THE AD ITSELF. INSTEAD IT’S JUST MAKING SPACE ON THE PAGE, AND THEN REACHING OUT TO A THIRD-PARTY AD SERVER LIKE DOUBLECLICK AND ASKING IT TO FILL THAT GAP WITH AN AD.
History’ to see the option to disable them. * In Edge, go to ‘Options > Settings > Advanced Settings’ and select the option to ‘Block on Third Party Cookies’ under the Cookies section. * In Chrome go to ‘Settings > Advanced > Privacy and Security/Content Settings > Cookies’ to find the switch to turn off third-party cookies.
INSTALL A FILTERING TOOL 02
There are browser add-ons that will block third-party tracking cookies, analytics tools and other things that can potentially be used to track you online (such as Facebook and Twitter widgets that dial back to their home servers).
The best of these are Disconnect ( disconnect.me) and Ghostery ( ghostery.com), which strip tracking elements out of websites, preventing them from dialling home to track your online activity.
03 INSTALL AN AD BLOCKER
Ad blockers prevent your browser from communicating with online ad servers at all. We’re a little squeamish about them because we understand that websites (including our own sister publications) need money to operate, but as long as ad services continue to monitor user activity, they’re a useful tool against them. Right now our top pick is uBlock Origin ( www.ublock.org).
04 TURN OFF GOOGLE ADVERTISING ID
Now we come to the stuff that affects mobile advertising. On Android devices, it’s called the Google Advertising ID. The Advertising ID is kind of like a browser cookie — if cookies applied to all mobile activity and not just web browsing. It allows advertisers to individually identify devices and use that to track ad-related activity on that device.
For example, if you tap on an ad in a mobile app, that mobile app can send your device’s unique Advertising ID up to the advertiser. That advertiser can then use that information, along with the device’s history of other clicks to build a customer profile of you: what you’ll click on, what apps you’ve used and so on.
We should note that the Advertising ID does not specifically identify you by name. It’s an anonymous code — just a string of random numbers and letters that serve to provide a persistent identity for your device. Of course, it’s not a huge leap for an advertiser to link an Advertising ID with an individual, especially if you make online purchases.
To turn it off, go to your Android device and find the Google Settings app in your App Drawer or the Google settings menu in Settings (tip for Samsung TouchWiz users: it’s found under Applications). Under Services, tap on Ads, then select the switch to ‘Opt out of Ads Personalisation’. Also tap on ‘Reset advertising ID’. Doing this resets your ID and prevents it from being sent in the future.
While we’re at it, go to adssettings.google.com in a browser and click the switch to ‘Turn off Ads Personalisation’ for your whole Google account. This will only apply to ads delivered by Google — including its AdMob (that’s the ads embedded in many Android apps) and AdSense (ads embedded in websites).
05 TURN OFF APPLE IDFA.
iOS has a very similar system to Android’s Advertising ID. On iOS, it’s called the Identifier for Advertising (IDFA), and it works on the same principle the Google Advertising ID — a unique device identifier that apps and sites can use to build a history of advertising-related activity.
We recommend you turn it off by going to ‘Settings > Privacy’ on your iOS device and tapping on Advertising. Enable the toggle for ‘Limit Ad Tracking’, and then tap on ‘Reset Advertising Identifier’ to delete your existing profile.
With that done, the amount of information that your mobile sends to advertising companies should be much reduced. And that can only be a net positive for your online privacy.