As a technical term, metadata was first described by computer scientists at MIT in the late 1960s. The concept behind it is much older than that, though.

Libraries have used tags to categorize their contents for thousands of years. Museums use metadata to manage their collections. The Internet transformed metadata into a powerful tool in its own right.

Every year, the number of data-generating devices and applications surges higher. The overall volume of data in circulation continues to grow even faster. People are buying more devices and putting more sophisticated applications on those devices than ever before.

This dramatically increases the amount of metadata available online. Anyone with resources and technical expertise can gather and analyze this data however they see fit.

What exactly is metadata?

Metadata is information that provides context about data. It often comes in the form of tags, labels, or other details that help categorize data and make it useful. When an application receives metadata, it makes it much easier to organize and manage the information it’s attached to.

Examples of metadata include:

• Geolocation data can accompany messages, photos, and videos, showing where in the world the data comes from. This kind of geographical data has many uses, like helping logistics providers solve inefficiencies in global trade.
• Device information includes details about the device that generated the data. For example, a file created on your phone may include metadata about the phone model, operating system, or IP address.
• Photo metadata may include the date a photo was taken, the camera settings used, or how the image has been encoded. Many professional cameras record the aperture and shutter speed of photos as metadata.
• Document metadata might include the author's name, the date the document was created, or the last time it was modified. Some document file formats support more types of metadata than others.
• Web and app metadata refers to browsing history, timestamps, and referrer data used by marketing companies. It also includes website cookies, tracking data, and application permissions.
• Communication metadata includes phone and email logs. These can show who you communicate with and how frequently. It may also include information about how the data is encrypted.

Why is metadata important?

Metadata helps make data easier to work with. It enhances the searchability and integrity of data, providing insights that help organizations make strategic decisions.

For example, a telecommunications company might use metadata to predict peak usage scenarios that might lead to outages and service disruptions. Analyzing peak usage times, geolocation data, and call quality can help the company proactively install capacity when needed.

On the other hand, the same company could use this data to pinpoint users in a specific region. It could build a detailed profile of users based on where they go, what apps they use, and who they communicate with the most. Then, it could sell this data to third-party advertisers without users’ knowledge or consent.

Both of these scenarios are strategic business decisions that rely on metadata. Organizations with access to this data can use it in practically unlimited ways.

Big Data analysis changes the game

Organizations with access to large volumes of data use sophisticated tools and algorithms to analyze and interpret that data because the datasets involved are too large and complex for traditional applications to interpret. Instead, they use an approach called Big Data.

When you have access to enough data, you gain the ability to analyze that data in new ways. Instead of manually processing every individual call log to learn about user behaviors, a telecom giant can infer user behaviors by looking at the big picture.

Big Data recognizes patterns and arrives at conclusions based on the large-scale movement of data in a system. Modern Big Data analytics use machine learning, predictive AI, and other technologies to accurately interpret large volumes of data in a system.

Notably, Big Data analytics lets organizations draw conclusions about user behaviors even with incomplete data. Contextual metadata often gives more than enough information to cover any gaps that might exist.

How metadata feeds Big Data

If the telecom company partners with another data provider, it can gain even deeper insights into its users. It may be able to find out users’ brand and vendor preferences and map out relationships between individuals.

From here, it can cross-reference the data it has on you with the data it has on other members of your network. It may see that you messaged a friend from out of town one week before the event, and then again at the stadium. If your friend is from the same place as the visiting team, the company may assume you also support that team.

This makes it easy to guess the content of your messages to your friend. It also lets the company build rich, highly detailed profiles for both of you based entirely on metadata.

Metadata can lead to real-world privacy violations

Most people would be comfortable with their phone carrier knowing what sports team they support. However, they might be less comfortable giving organizations information about their mental health.

A four-year study at Dartmouth college used telephone metadata to track students’ well-being and mental health. It used this data to infer which students were at risk of stress-related disorders, low self-esteem, and depression. The study’s authors made the dataset available to the public in anonymized form.

It’s one thing to entrust this kind of information to an Ivy League university running a research program. However, it would be trivial for a large technology company to gather the exact same kind of data on millions of mobile phone users.

Very few people would be comfortable letting large advertisers, search engines, and social media companies know about their mental health issues. The risk of abusing this information to exploit vulnerable people for financial gain is obvious—but also perfectly legal.

The sheer volume of metadata available in today’s internet-connected environment means almost everyone is at risk of this kind of exploitation on some level. Paying close attention to the data you share with the world is more important than ever.

How to gain control over your metadata

Fortunately, almost all mobile devices and applications include features to control the amount of metadata you share. Here are some of the most important steps you can take to improve data privacy right now:

In today’s digital landscape, metadata is the backbone of Big Data—driving innovation, efficiency, and insights. But it also comes with a trade-off: the more metadata we generate, the more exposed we become to surveillance and exploitation. From telecom companies inferring personal details to advertisers building intricate profiles, the risks are real and often invisible.

The good news is that you don’t have to accept this as the status quo. Simple steps—like turning off location tracking, using encrypted messaging apps, and limiting app permissions—can go a long way in reducing your digital footprint. While it’s nearly impossible to stop generating metadata altogether, being mindful of what you share and taking control of your settings can help you protect your privacy online.