It won't come as much of a surprise that Facebook tracks you on its platform—that's why it can resurface your birthday photos from five years ago—but you might not yet realize the scope and the depth of its tracking all across the internet. Facebook's tentacles stretch out across other websites and services, into the various apps you're using on your phone, and to the places you physically visit in the real world—especially if you decide to check in on Facebook while you're there.

Some of this comes with the territory of using Facebook: If you want to take advantage of its features, then you have to give up a certain amount of information about yourself. But Facebook has ways of keeping tabs on people who aren't even signed up for the service. Fortunately, there are numerous ways to limit the volume of data that it logs.

How hard you want to pull back depends to a certain extent on how much you trust Facebook. The social network behemoth says it uses your data to show relevant ads and keep you safe; if someone signs into your account from a country you're not usually in, for instance, Facebook can flag the activity as suspicious.

However, this is not a company with a good track record when it comes to looking after your data. Irrespective of how Facebook itself has used your information, it's certainly been careless in the ways that information has been shared with third parties.

To make matters more complicated, Facebook owns WhatsApp and Instagram too, and can pool some of the information it gathers in those apps as well. The best way to limit Facebook's tracking is to quit all three apps for good. If that's too extreme for you, we've got some more suggestions.

For reference, the Facebook data policy is here, and you can read a more user-friendly explainer on how your data is handled here.

On the Web

Courtesy of Facebook

If you want to use Facebook, you give it permission to log your activity on the site: where you check into, the groups you join, who you interact with. This data is primarily used to serve up advertising that's more relevant to you, which in turn makes more money for Facebook.

You can't really stop Facebook from collecting this information—it's the deal you make when you sign up—but you can limit how it affects the advertising you see by visiting the ad preferences page in your account on the web. Open up Your interests to get a quick glance at what Facebook thinks you're into. It might have made some assumptions that are well wide of the mark.