Everyone knows that Facebook collects personal data, but shadow profiles are one of the more intrusive methods the social network uses.

In a nutshell, shadow profiles mean that even if you've never used Facebook, the website may have information about you stored away.

So, in order to help you maintain your privacy, in this article, we'll explain what Facebook shadow profiles are, and what you can do about them.

What Are Facebook Shadow Profiles?

Facebook's sign up screen

Shadow profiles are so-called because they're not something you make yourself. Instead, Facebook creates shadow profiles without your knowledge or consent.

Let's suppose you don't have a Facebook account. One of your friends, however, makes an account on Facebook. Facebook offers them a special service where they can import their contacts to find friends already on the service.

Your friend thinks this is a great idea, so they import their contacts list to Facebook. Facebook can then go through the contact details and let your friend know if any of their friends have also made an account.

However, while it's scanning the list, Facebook will find the contact details of people who aren't signed up yet---including you. Ideally, Facebook would understand that you haven't signed up for an account and would leave the information alone.

However, this is Facebook we're talking about, and passing up the chance to obtain free information isn't its modus operandi. Instead, Facebook will create a shadow profile for you behind the scenes, allowing it to store your personal data. This occurs without your consent or knowledge.

As such, even if you've sworn off ever using Facebook, the service may still know your name and contact details. If you have friends that use and import their contacts to Facebook, you can never assume Facebook doesn't have your information.

Unfortunately, while Facebook does allow you to download the data they have on you, it's currently only possible if you have an account with them. As such, you need to give up more personal information to see your profile, which isn't an ideal trade-off for the privacy-minded.

How Do We Know Facebook Creates Shadow Profiles?

The Facebook post reporting the initial leak of shadow profiles

Unfortunately, Facebook shadow profiles aren't just a rumor or conspiracy theory. They came to light after Facebook discovered there was a leak of people's contact details all the way back in 2013.

Leaks typically reveal registered user's details who willingly gave information to the website. However, Facebook's breach somehow revealed information for people who had never signed up to the website. This raised eyebrows and revealed the existence of shadow profiles.

Why Does Facebook Create Shadow Profiles?

Facebook's "People You May Know" feature

So, why does Facebook create and store shadow profiles on people who have no interest in using Facebook? It depends who you ask...

If you ask someone from Facebook, they'll say that shadow profiling is essential for the "People You May Know" feature. This is where Facebook recommends friends you may know that have accounts on the website.

The idea is that if Friend A and Friend B both make a Facebook profile before you, Facebook can get an idea of who is in your circle of friends. For example, the social network can see that you're in both Friend A and Friend B's contacts. As such, there's a chance both of these friends know each other, too.

This gives Facebook a somewhat-uncanny ability to pair you up with the people you know when you first sign up. This is Facebook's rationale behind the data collection, and it claims it needs shadow profiles to achieve this.

If you ask anyone else why Facebook collects this data, you'll probably get a more cynical answer. In the modern age, hoarding information on people can be very profitable.

When people give Facebook free data, the service will do everything it can to ensure it harvests as much value from said data as possible. It even goes so far as to keep information after you delete your account, as we covered in our article about deactivating or deleting your Facebook account.

Has Facebook Disclosed These Activities?

Since shadow profiles became public knowledge, Facebook has updated its Privacy Policy. In it, they state that it does use local information from your phone.

Under the section "Networks and Connections," Facebook says:

"We also collect contact information if you choose to upload, sync or import it from a device (such as an address book or call log or SMS log history), which we use for things like helping you and others find people you may know and for the other purposes listed below."

And under the section "Things others do and information they provide about you," Facebook states:

"We also receive and analyze content, communications, and information that other people provide when they use our Products. This can include information about you, such as when others share or comment on a photo of you, send a message to you, or upload, sync or import your contact information."

The last bolded part is the key line that lets Facebook continue to make shadow profiles. As long as users agree to this privacy policy and continue to entrust Facebook with their data, Facebook will continue to use contact information to create shadow accounts.

Is There Anything You Can Do About Shadow Profiles?

Unfortunately, you don't have any direct control over shadow profiles on Facebook. Whenever a Facebook user who has you as a contact on their phone signs up to Facebook, your information will be added to your shadow profile.

You CAN ask your friends to delete the contacts they've uploaded to Facebook. They can do so by heading over to the Manage Contacts page on Facebook. Of course, they will have to keep the sync settings turned off after this.

Managing imported contacts in Facebook

Unfortunately, this isn't very practical. You would have to ask everyone you know who a. has your contact details and b. is on Facebook to follow the procedure. If even one friend doesn't comply, they'll eventually upload your data to Facebook.

As such, the best way you can protect yourself from data harvesting is to give your friends some "burner" details. Have an email and phone number which you freely give out to friends, while keeping your personal information private.

It's a lot to ask, but it's the only real way you can prevent Facebook from harvesting your data. When a friend adds you as a contact and syncs their contacts with Facebook, your shadow profile is created. As such, the only way to prevent it is to create a new, private email address.  Then, only allow close friends and family without Facebook to contact you with it.

Maintain Your Privacy While Using Facebook

Facebook has been, and will likely continue to be, a big sore spot for privacy enthusiasts. It's likely that Facebook already knows all about you, even if you've never visited its website.

The only way to avoid it is to ditch your publicly known information and use a private email address and phone number. Then, you can only share this information with people you trust and know aren't on Facebook.

If you want to know more about staying safe while using Facebook, be sure to read the complete Facebook privacy guide.