What does metadata do?

By Joe Pairman

All digital publishing relies on metadata. In structured content — one of Mekon’s specialisms — metadata mixes with content throughout each document or file. But what is it exactly? What’s it good for, and how do we use it best? Follow this series to find out.

By BruceBlaus (Own work) [CC BY-SA 4.0], via Wikimedia Commons

Metadata is to content as labels are to groceries. Labels tell you what’s inside a product; who made it; who should and shouldn’t consume it; even how long it’s good for. Metadata gives you similar information, but for content.

Why do we need it? Can’t we just read through content to find out what it’s about and judge whether it’s relevant? That works on a small scale — a single user manual, perhaps, or a one-page site for a local business. However, when we handle information on a larger scale, we need a better way to manage it. Library cataloguing systems such as Dewey Decimal are a classic example. Without them, it would be impossible to find the book we wanted. In the same way, imagine a warehouse stacked with products from around the globe. Barcodes stuck onto each product let us keep track of what items are where and what needs to be restocked. Content often needs managed on a warehouse scale or even greater. Labels make groceries and content searchable, manageable and, crucially, transportable between locations or systems.

For example, health information sites must keep their thousands of pages of content up to date. Each page probably has an associated “to-review” date. When that date comes up, perhaps the page needs to go back to the original author for review. Their username is associated with the page, so it can be routed automatically to their inbox. It may be that the content is managed separately from the presentation platform — in this case, the username may be automatically transformed into the author byline on the published page.

Much metadata helps with shuffling bits of content around behind the scenes. However, large portions of a site or app’s visual navigation may be based on metadata. Just as successful online supermarkets work on their taxonomies, so content portals allow users to combine filters and rapidly find the information they need.

Screen capture from Cisco.com by Peter Morville on Flickr

Other common appearances of metadata include:

Search results in Google that include star ratings, images or procedural steps
Date stamps and author bylines in news apps on our phones
The information that lets the Transport for London TravelBot give me a link to the “Planned works” page when I ask about closures over New Year

Not all metadata is digital, however. It is true that digital capabilities give us unprecedented power to manage content, including small chunks of “microcontent” — interesting to those of us working with XML or JSON-based content. But much of our modern thinking on metadata originates in the early computer age, or even the analogue age. For example, the faceted filters shown on the Cisco page come directly from the thinking of librarian and mathematician S.R. Ranganathan in the early 20th century.

In this series, we’ll continue to find useful examples of metadata in the analogue world. Later, we’ll return to the groceries, as they have more to teach us about efficiently labeling and handling content. In the next piece, however, we’ll hear how all metadata is structured like simple spoken sentences.

Learn about Mekon’s metadata and taxonomy services, or email us for a chat about any of your metadata challenges or questions.