What Is a Shadow Profile? Data Held on Non-Users

Platforms can hold data about people who never signed up, often through other people’s contact lists.

By Siddharth ShankarUpdated October 22, 2026

You do not have to use a social network for it to know something about you. The term “shadow profile” describes that situation. It is not an official product name, and what companies actually hold is often unclear.

What a shadow profile is

A shadow profile is information a platform holds about people who are not users, or details about users that they never provided. It comes from other sources. Facebook does not use the term, according to How-To Geek’s explainer.

The 2018 hearing

On April 11, 2018, Representative Ben Luján questioned Mark Zuckerberg at a House Energy and Commerce Committee hearing. TechCrunch reported that Luján asked whether Facebook has detailed profiles on people who have never signed up. Zuckerberg answered that “we collect data on people who have not signed up for Facebook for security purposes”, and tied that to preventing scraping, such as reverse searches using public information like phone numbers.

Asked whether “shadow profiles” was the name some people used, Zuckerberg replied that he was not familiar with it. Luján said he would use the term for the hearing. Zuckerberg also said anyone can opt out of data collection for ads, whether they use Facebook’s services or not. Luján argued that non-users never consented, and noted that Facebook’s page for non-users to request their data pointed to a download that needs an account.

How the data can be collected

How-To Geek lists likely sources rather than confirmed methods:

• Contact uploads. When a user lets an app read their phone contacts, the platform sees the names and contact details of people who are not on it.
• Friends’ content. Friends can post photos or details that reveal information about you.
• Matching on the web. Once a company knows your face, email or phone number, it could look for more public information.

Why it matters to you

The same data can power features such as people suggestions. Our guide to People You May Know shows how an unfamiliar name can appear in your suggestions because of someone else’s contacts.

What you can do

• Limit what you give out. The fewer places your number and email appear, the less there is to match. See data minimisation.
• Tighten your own account. Use Facebook’s privacy settings and review off-Facebook activity.
• Use opt-out signals. Turn on Global Privacy Control where it is honoured.
• Ask for your data. Where a law gives you access rights, you can ask a company what it holds.

An honest limit

How-To Geek’s advice is that avoiding personal data online is not practical for most people. Reduce what you can and be realistic about the rest.