Facebook has a new way to make money off of your data—and, potentially, to learn more about you than it ever could before.
If you’re a Facebook user, the company’s machines already know all the things you’ve explicitly told Facebook over the years, like your name, age, email address, friends, likes, and interests. They also already know how you behave on Facebook, including which types of stories you’re likely to click on and which friends’ status updates you like the most.
Now they’re beginning to learn more about how you behave when you aren’t on Facebook. For instance, they have the ability to know whenever you visit a Web page that has a “like” button. For years Facebook insisted it wouldn’t use this sort of data to track your activity for commercial purposes. Recently, it decided it might start doing that after all.
On Monday, the company announced the next step: a new advertising platform called Atlas. Atlas will allow advertisers to harness Facebook’s data about you to target you on non-Facebook sites and apps, with ads not purchased through Facebook. Again, these are not Facebook ads, and they won’t be shown on Facebook—but they’ll be drawing on all of Facebook’s knowledge of you as an individual in order to target you. They’ll be able to do that even if you’re not logged into Facebook and have browser cookies turned off, although you can still block it by selecting "limit ad tracking" on your iPhone or "opt out of interest based ads" on your Android device.* Facebook calls this "people-based marketing."
The move puts Facebook in direct competition with Google’s DoubleClick service, offering advertisers the chance to target users and measure their ads’ reach on a potentially wide array of sites as well as mobile apps. The potential edge, for Facebook, is that Atlas won’t rely on browser cookies. Cookies can be cleared, they don’t cross from one browser to another, and they’re notoriously ineffectual on mobile devices. Google has been working to address this problem. But with Atlas, Facebook may be leaping ahead.
If you’ve ever logged into Facebook on your phone, Facebook has linked your phone’s unique identification number to your Facebook account. So when you use another app or a different browser on the same device, Facebook’s computers still know it’s you, and Atlas will be able to use that information to help advertisers reach you. Visit a site from your desktop computer using a browser on which you've logged into Facebook, and Facebook will know you’re the same person who visited it from your mobile phone awhile back.
Facebook has responded to privacy concerns by clarifying that Atlas won’t actually give third-party advertisers any information about you. It will just use that information to make sure they’re reaching their intended audience.
But one of the biggest long-term impacts of Atlas may be to expand Facebook’s own ability to track you across the Web and mobile apps. When you visit a site that uses Atlas to serve ads, you’ll be giving Atlas more information about yourself that it could potentially add to the ever-expanding database that Facebook has on you.
A Facebook spokesman told me that the information Atlas gleans about your browsing habits will not be sent back to Facebook. “Atlas doesn’t tell marketers who you are, and Atlas also doesn’t share information about you back to Facebook,” he said. Of course, Facebook has been known to change its mind about such things. When I asked the spokesman if he could promise users that Atlas would never share this information, he declined to comment.
*Update, Sept. 30, 2014: This post has been updated to clarify that it is possible to opt out of Atlas ad targeting on mobile devices.