Metadata is data about data. In other words, it’s information that is used to describe the data contained in something like a web page, document, or file. Another way to think of metadata is as a short description or summary of what the data is.

A simple example of metadata for a document might include a collection of information such as the author, file size, date the document was created, and keywords to describe the document. Metadata for a music file may include the name of the artist, album, and year of release.

For computer files, metadata can be stored in the file itself or elsewhere, as is the case with some EPUB book files which store metadata in the associated ANNOT file.

Metadata represents behind-the-scenes information that is used everywhere, by every industry, in a variety of ways. It is ubiquitous in information systems, social media, websites, software, music services, and online retail. Now, metadata management tools can be created manually to pick and choose what is included, but it can also be generated automatically based on the data.

Metadata comes in several types and is used for a wide variety of purposes which can roughly be categorized as business, technical, or operational.

• Descriptive metadata properties include title, subject, genre, author, and creation date, for example.

• Metadata rights may include copyright status, rights holders, or license terms.

• Technical metadata properties include file type, size, creation date and time, and compression type. Technical metadata is often used for digital object management and interoperability.

• Preservation of metadata used in navigation. Examples of preservation metadata properties include where items are in a hierarchy or order.

• The markup language includes metadata used for navigation and interoperability. Properties may include title, name, date, list, and paragraph.

Metadata and Website Search

The metadata embedded in a website is critical to the success of the site. This includes website descriptions, keywords, metatags and more – all of which play a role in search results.

Some of the common metadata terms used when creating web pages include meta titles and meta descriptions. The meta title briefly describes the topic of the page to help readers understand what they will get from the page if they open it. The meta description is further information, albeit brief, about the content of the page.

These two pieces of metadata are displayed in search engines for readers to see at a glance what the page is about. Search engines use this information to group similar items so that when you search for a specific keyword or keyword group, the results are relevant to your search.

Web page metadata may also include the language the page is written in, such as whether it is an HTML page.

Metadata for Tracking

Retailers and online shopping sites use metadata to track consumer habits and movements. Digital marketers follow your every click and purchase, storing information about you such as the type of device you use, your location, the time of day, and any other data they are legally allowed to collect.

Armed with this information, they create a picture of your daily routine and interactions, your preferences, your associations, and your habits, and can use that image to market their products to you.

Internet service providers, governments, and anyone else with access to large collections of metadata information could potentially use metadata from web pages, emails, and elsewhere there are online users, to monitor web activity.

Since metadata is a short representation of larger data, it can be searched and filtered to find information about millions of users at once and track things like hate speech, threats, etc. Several governments have been known to collect this data, including not only web traffic but also phone calls, location information, and more.