Even if you’ve never heard the term metadata, you’re definitely familiar with it – you probably use it every day without even realizing it. Metadata is one of those important things that can hide in plain sight.
What is Metadata?
Metadata sounds like an intimidating term, but it’s not—metadata is simply information that describes other information.
In many ways, metadata is like a driver’s license or any other identification card you’re familiar with. An official ID will usually include your date of birth, height, eye color, photo, and other information about you. Metadata fulfills a similar role for digital files on computers. Metadata will usually describe when a file or folder was created, when it was last modified, and other important attributes about it.
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Different types of files will often have different metadata. Here are examples of metadata added to common files.
Examples of metadata
The information stored as metadata varies significantly between file types. As you can imagine, pictures or images require different metadata than, for example, a text document.
Photos and Video
Let’s say you’re on a hiking trip using your phone’s GPS to guide you. While on a trip, you pulled out your phone and snapped a photo of an animal, a strange mushroom, or a scenic landscape. As soon as you take a photo, it has information attached to it: camera settings, including exposure length, ISO, F-stop, camera manufacturer, time the photo was taken, and possibly the photo’s GPS coordinates. camera when the picture is taken.
Once this data is saved, it can be used to sort and categorize images. The photo gallery app on your phone is a good example – you can sort your photos by date and even by location if you’ve enabled geotagging. Modern photo gallery apps can even add additional information that describes the content of the photo, such as “Food,” “Pets,” or a specific person’s name. This is what allows you to search for images on your phone based on their content. An example of a photo taken with the phone’s GPS enabled:
You can directly view the image metadata on your phone or PC.
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The GPS metadata attached to the image is only as accurate as the GPS on your cell phone, but in most cases it’s accurate to within a few meters.
Video files will have much of the same information, and then some additions related to the frame rate and audio associated with the video.
Audio metadata will include the usual things like when the file was created, but it also stores information specific to audio files. Metadata for audio files typically includes information about the audio itself, such as artist, album, track number and title, as well as bitrate, bit depth, and sample rate.
Messages you send to other people also have associated metadata. Typical examples of metadata added to messages are information about the time it was sent, the recipient, and any attachments the message may contain. Some messaging apps may place additional metadata in their messages, such as reception time and emoji reactions.
A particularly important type of metadata is the file extension. File extensions are PNG, TXT, DOCX, JPG, MP3, etc. things like A file extension lets Windows know what data to expect and how to open the file. Without it, Windows won’t automatically know how to open it, and you’ll have to manually tell it to open the file using a special program.
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Note: Not all operating systems use file extensions to store file format metadata.
Various computer files
Most files have metadata that is fairly specific to the file type, but there are certain metadata that are mostly universal. If you check the properties of almost any file on your computer—regardless of the file type—you’ll see information about where the file is stored, when it was created, when it was accessed, when it was modified, and when it was modified. was created. An example from Windows 10:
How is Metadata Used by Individuals?
If you use any modern computer, including a mobile phone, you use metadata regularly. Metadata is what allows you to sort your files by type. This allows you to order your files by “Date Created”, “Date Modified” or “Date Accessed”. Most modern media players let you list your music by bitrate or categorize your movie library by resolution. Web sites often contain “meta tags,” a special type of metadata found in the title of a Web site that is used to describe the Web page’s content to a search engine.
When you categorize files, folders, or websites, you rely on metadata.
How else is metadata used?
Individuals use metadata in specific ways, but what about the big picture? Everything you do on a computer creates data and metadata. Consider that there are tens of billions of computers in use today, including six to seven billion smartphones – we collectively generate an incredible amount of metadata every day.
Targeting of Ads and Content to specific people
This information is not simply thrown away. A large part of this is fed into sophisticated algorithms and machine learning models for analysis. What happens next really depends on who collects the metadata and what they want to learn – it can be used to analyze everything from an individual’s behavior to larger patterns and trends in society.
The most common face-to-face use cases are targeted advertising and personalized content offers. Have you ever found your social media feed on your phone loaded with ads about something you’re looking for? Have you ever clicked on something unusual on YouTube only to find that your suggestions have changed to include more results like the one you just clicked on? I mean algorithm at work, crunching the data and metadata associated with you to show results it “thinks” are likely to catch your eye and get you to click.
Using metadata to enhance user engagement has some unintended consequences. Most notably, it favors content that is emotionally extreme: either makes you feel really good or really bad—both of which are usually more stimulating than the actual content. That’s a big part of what makes mindlessly scrolling through social media so incredibly addictive.
This sometimes results in ads that people find quite invasive—there’s nothing like checking WebMD when you’re feeling under the weather, only to find your Facebook timeline loaded with ads for drugs that treat a laundry list of conditions that explain your symptoms.
Note: Facebook has, among other things, promised to block some medical ads and has previously added additional restrictions on drug ads. We will see how these changes will play out in the future.
Of course, even if social media policies change and these things stop appearing on your social media feeds, that doesn’t negate the fact that the information is out there and usually available to the highest bidder. Historically, much of your sensitive information has been protected by law – for example, HIPAA in the US protects your medical information from being transferred or used except under very specific circumstances. However, many jurisdictions have such protections for information derived from your metadata, although this varies.
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Metadata Collected for Monitoring
There are many uses for metadata beyond just advertising and targeting content. Among the most controversial is observation. Edward Snowden caused great controversy when he presented evidence that the United States’ National Security Administration, among other things, collects metadata from hundreds of millions of text messages every day.
Police can do something similar, albeit on a smaller scale, using a stingray tower. Stingray towers mimic real cell phone towers so that nearby cell traffic passes through them. In this case, the type of data intercepted may vary – everything transmitted unencrypted will likely be completely readable, whereas if communications are encrypted, only some metadata will be exposed.
Note: Some messaging apps (like Signal) go out of their way to minimize the amount of unencrypted metadata, and they say they don’t store metadata either.
Even without the actual content of your messages, there’s enough information in the metadata to learn who you’re communicating with, when you’re talking to them, and potentially even your actions.
Is metadata a privacy concern?
Most every digital file out there will have some metadata associated with it – sometimes the file itself has metadata, other times the metadata is stored separately by the operating system. The metadata of most videos and images uploaded to the Internet is now automatically removed – all major social media sites and most image hosting platforms remove metadata, and Slack, Discord, WhatsApp, Facebook Messenger, Signal, and Telegram.
Warning: Uploading your photos to a cloud storage service will not remove the metadata, so be careful when sharing photos this way. Emailing images will also not delete metadata.
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More importantly, everything you do creates metadata. Metadata is created when you send or receive data over a mobile network or the Internet. This data is collected by both governments and private companies and can be used to analyze the behavior of individuals or groups.
Given how pervasive metadata is and how revealing it can be, this is clearly a privacy issue.
Most smart devices collect usage data, and the Internet of Things (IoT) is only set to expand the amount of data and metadata collected. Your metadata can often be as public as your data. Take steps you can to protect your privacy and be careful when uploading information to the Internet.
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