Metadata are structured assertions that describe some form of communication. Metadata are usually used to assist in the organization, discovery, use, and management of these communications.
Metadata can be machine-generated, human-generated, or generated by a combination of these approaches. Some examples of metadata:
- A library catalog card, which is a structured expression of information that describes a book and its content
- EXIF data as recorded by a digital camera or smartphone, which describe a digital photograph (see thumbnail on the right)
- ID3 metadata, which allows a song's title, artist, album, and track number to be stored within an MP3 file.
- CDWA records for works of art in museums.
- This page's history log, which documents all changes to the page you are viewing right now.