What is Metadata?
Metadata is data that describes other data. It records a file, web page, or dataset’s attributes, such as author, creation date, file size, or file type, and can live inside the file or be stored separately. On a web page, metadata includes elements like the title tag and meta description.
More About Metadata
On a website, metadata is added through meta tags: HTML elements that give search engines and browsers information about a page’s content. You can use metadata to set a page’s title tag, write a meta description, and describe images with alt text. Schema markup counts as page metadata, too: structured data that describes your content to machines.
Meta tags belong in a page’s <head> section. This single line sets a meta description: <meta name=”description” content=”Learn how to bake sourdough bread at home.”>. Visitors never see that sentence on the page, but search engines read it.
What each kind of page metadata does
Each element has a specific, documented job, so add metadata for the job you need done, not in bulk:
- The title tag names the page and helps search engines understand what it’s about.
- The meta description can become your snippet: Google builds snippets primarily from page content, but it may use your meta description when that describes the page better.
- A robots meta tag controls crawling and indexing. A noindex value asks search engines not to index the page at all.
- Alt text describes an image in words, for screen readers and for search engines.
- Structured data classifies your content in a standardized format and can make the page eligible for rich results, the more engaging result formats.
Quality beats quantity here. Google’s documentation on supported meta tags is explicit: clients process the meta tags they support and ignore the rest, so piling on extra tags does nothing. Fill the fields that do a job you need, keep them accurate, and skip the rest.
The three types of metadata
Metadata comes in several types, each describing a different aspect of the data:
- Descriptive metadata identifies content: a document’s title, author, keywords, and creation date.
- Structural metadata shows how pieces relate, the way a table of contents maps a book’s chapters or a home page links to its subpages.
- Administrative metadata covers management: who owns the data, who can access it, and how long to keep it.
IBM also counts technical metadata (file format, resolution, storage location) and preservation metadata (the information that keeps stored data usable over time) among the common kinds.
Metadata in files and photos
Every file on your computer carries metadata whether or not you add any: the file system records details like its size, type, and when it was last modified. Photos carry more. Cameras and smartphones embed EXIF data, including the camera model, exposure settings, a timestamp, and often the GPS coordinates of the spot where you pressed the shutter. That last field is the one to watch: publish an unedited photo and anyone can read exactly where it was taken. Review or strip EXIF data before uploading photos from places you’d rather not share.
Web metadata is easier still: you rarely need to edit HTML files by hand. If your site runs on WordPress, most SEO plugins provide simple fields for adding metadata, like titles and meta descriptions, to your posts and pages.
Frequently Asked Questions
How do I find or view metadata?
On Windows, right-click a file and choose Properties; on a Mac, select the file, then choose File > Get Info. For a web page, right-click, choose View Page Source, and look for the meta tags near the top, inside the head section.
What’s the difference between data and metadata?
Data is the content itself; metadata describes that content. A photo is the data, while its capture date, camera model, and GPS coordinates are its metadata. You can usually edit or remove metadata without changing the content it describes.
How do I remove metadata from a photo?
Check your photo editor or a dedicated metadata-removal tool for an option to strip EXIF data. Removing it doesn’t change the visible image, so strip metadata from any photo whose time or location you’d rather keep private.
What is metadata in a database?
A database’s metadata describes its structure: its tables, their data types, and the relationships between them. IBM classes this as technical metadata. Database systems rely on metadata to sort, retrieve, and manage the data they hold.
