This image was removed due to legal reasons.

Four years ago, Facebook promised that the “Like” buttons that had sprung up on non-Facebook sites all around the web wouldn’t be used to track users. In 2011, Facebook said, “No information we receive when you see social plugins is used to target ads; we delete or anonymize this information within 90 days, and we never sell your information.” Back then, Facebook said it only used the information to target you if you actually clicked on one of its off-site Like buttons. Which calmed the privacy storm at the time.


But then the big blue giant realized the gold mine it was sitting on and it changed its mind.

Now, every time you visit a site or use an app that has a Facebook “Like” or “Share” button, data about your visit will be captured and fed into Facebook’s advertising algorithm, even if you don’t actually click on the buttons. Millions of sites use Facebook’s off-site buttons, including many popular news sites, e-commerce sites, and, yes, adult entertainment sites. In other words, as security technologist Nicholas Weaver put it, Facebook ads could now reflect your taste in porn.

Or, as I put it: “Facebook Likes your taste in porn.”http://t.co/J0rcrCfQ2r — Nicholas Weaver (@ncweaver) September 18, 2015

Facebook made the announcement about the change last year, but it goes into effect next month, according to the Technology Review. What has historically disturbed people about this feature is the idea that they’ll be targeted with ads not because they actively told Facebook they liked something, but just because they stopped by a page that happened to have a Facebook button on it. With the huge percentage of the web that uses Facebook “Like” and “Share” buttons, Facebook will now effectively be able to use a significant portion of every user’s browser history to determine what ads they’re shown.


But getting ads based on your porn habits may not be the worst of it. Now, every site you visit with a Like button will become part of your Facebook ad profile, even if there’s no context about why you were visiting that site. That means if you hate-read an article on a site you disagree with, you may start seeing ads that assume you loved the article’s subject. If you visit Planned Parenthood’s site—which has Facebook share buttons at the bottom of articles about abortion and birth control—Facebook’s advertising algorithms may start making some assumptions about your birthing plans. Instead of getting outed by being invited to join a Queer Chorus Facebook group, a closeted teen’s sexual preferences might start being reflected in his Facebook ads after he reads articles on Out Magazine.

Cookies have always followed your computer’s trail around the web. But the difference when Facebook tracks you is that it gets to pair your browsing history with a robust profile that you’ve given it about who you are, who your friends are, and what you like.

Part of why people were initially comfortable with the colonization of websites with “Like” buttons four years ago was Facebook’s reassurance that those buttons were not being used to track and profile them. From a cynical perspective, this is the privacy long game. You get people used to seeing “Like” buttons for enough years, and eventually, they just assume they’re being tracked.


“I’m actually shocked this hasn’t been the case all along,” tweeted New York Times technology reporter Mike Isaac in response to the Technology Review story about the use of the presence of Like buttons for ad targeting.

That is exactly what they want you to think!


The good news: If you don’t want your browsing history determining the kinds of Facebook ads you see, there’s a way to opt out, as described in a blog post this week from Facebook’s chief deputy global privacy officer.

This image was removed due to legal reasons.


Of course, even if you opt out, Facebook will still know you were on the porn site. But it won’t use that information to serve you ads. This is a reminder to the sites of the world that, if they’re hosting sensitive content that their visitors might not want Facebook to know about, they should think twice about putting “Like” buttons on every page.