What is metadata? Understanding the type of data that describes data sets and determines much of what you see online

• Metadata is a term for data that describes the attributes of another set of data.
• Metadata can determine much of what you encounter online, from the top search results returned in Google to the contents of the ads you see.
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"Metadata" is one of those techy buzzwords you'll frequently hear in the discourse surrounding internet privacy, storage, and social media.

There's an array of applications of metadata - a few of which you may find pertinent to your online life.

Here's everything you need to know about metadata and how it applies to your internet habits.

What is metadata?

There are several varieties of metadata, but in a nutshell, metadata is simply data that describes attributes of another set or sets of data. Metadata can describe the size, time created, and other aspects of data.

For example, when you compose an essay in Microsoft Word, the words within the .doc file represent data within the document. The metadata, on the other hand, are attributes about the .doc file, which could include the time the .doc was most recently modified, the time the .doc was created, or the size of the file in megabytes.

Types of metadata

The following are several of the most common types of metadata, with "descriptive" being the most common.

• Descriptive metadata: You can think of descriptive metadata as a type that sheds light on the basic biography of a piece of data - details like the title, date published, and who the creator is. The metadata described in the Microsoft Word example above is known as "descriptive" metadata.
• Use metadata: Another type of metadata is "use" metadata, also known as tracking metadata, which is the data that keeps record of when and how often a user interacts with a piece of digital data. This kind of metadata could, for example, help inform an influencer what time of day is best to post on Instagram.
• Administrative metadata: This type is also sometimes called preservation metadata. This metadata keeps a record of who has owned or altered the digital object, and preserves the data's rights, permissions, and specific instructions to gain access.
• Provenance metadata: This applies to data that is frequently modified or replicated. One example of provenance metadata could be the "Revision history" section of a Wikipedia page.

• Structural metadata: Within the broad categories of metadata, there's "structural" metadata, which is information pertinent to properly arranging, or rearranging, sections within a data set that the metadata describes.

How metadata is used

Metadata is used in ways that affect all aspects of life, particularly online.

• When you do a Google search, the top results are no accident. From a website's keywords to the naming of its .jpg files, these results are packed with metadata that help solidify their pertinence to your online inquiry and determine how high up on the results page they appear.

• If you've ever been unexpectedly emailed by an online retailer, that may have been based on use (also known as tracking) metadata. For instance, if you've taken a prolonged break from buying cosmetics, a company's use of metadata might trigger an email that seeks to reboot your beauty product addiction.
• Speaking of metadata that tracks you, have you ever noticed that ads for the online retailers you've visited in the past seem to follow you everywhere? It's not in your head, but is actually another instance of metadata in action.
• A time when you might add your own metadata is if you're a DJ who wants to see additional data attributes within your digital music library, like beats per minute or the key a song is in.

• You can use descriptive metadata to keep tabs on your computer or phone storage by sorting and trimming the largest files from a device.