How Facebook Collects Data About You to Target Ads (And How You Can Change That)

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Facebook knows a lot about you, like where you work, where you live, and your relationship status. But that only covers the personal details you elect to make public online—there’s a whole list of undisclosed information Facebook compiles on each of its users for advertising purposes. If you’re not ready to delete your account for the sake of privacy, you can review and edit your own list of categories for targeted ads in a few quick steps.

A recent episode of the podcast Reply All delved into how Facebook chooses ads based on the preferences and lifestyles of its users. Cat lovers may see ads for cat food pop up beside their news feed, for instance, or someone planning a vacation may be shown ads for hotels. Sometimes, the specificity of these advertisements can feel very creepy. The hyper-targeting has even convinced some users that Facebook is eavesdropping on their private conversations through their devices (which Facebook denies), but the truth is that Facebook has learned enough about the kind of person you are to make really accurate educated guesses about what you want to buy.

So what exactly are the details Facebook looks at when targeting ads? You can find them by going to your “ad preferences” page, clicking on “your information,” and then going to “your categories.” There you’ll find everything from your political leanings and the industry you work in to the devices you own. Facebook doesn't always get these things right, but you may be surprised to learn how much the site knows regarding areas of your life you’ve never posted about in the past. I hardly ever update my profile, but according to my categories page Facebook somehow knows that I live with roommates and that I like to travel. That's because some of this information isn't based on my Facebook activity, but on information Facebook gets from my behavior on other sites.

You can get Facebook to stop using these categories to target ads by clicking the “X” beside the entry. But don’t expect the targeted ads to disappear after purging the page—according to ProPublica, the “your categories” section doesn’t paint a full picture of what Facebook thinks you like (for a more complete version of that list, you can download ProPublica’s Chrome extension).

Want a better way to get rid of targeted ads? Go back to the “your ad preferences page” and click on “ad settings.” From there, you can disable the “ads based on your use of website and apps option.” That way you can online shop without ads for the item you just bought following you back to social media.

[h/t Reply All]