Metadata (meta data, or sometimes metainformation) is "data about data", of any sort in any media. Metadata is text, voice, or image that describes what the audience wants or needs to see or experience. The audience could be a person, group, or software program. Metadata is important because it aids in clarifying and finding the actual data.An item of metadata may describe an individual datum, or content item, or a collection of data including multiple content items and hierarchical levels, such as a database schema. In data processing, metadata provides information about, or documentation of, other data managed within an application or environment. This commonly defines the structure or schema of the primary data.

For example, metadata would document data about data elements or attributes, (name, size, data type, etc) and data about records or data structures (length, fields, columns, etc) and data about data (where it is located, how it is associated, ownership, etc.). Metadata may include descriptive information about the context, quality and condition, or characteristics of the data. It may be recorded with high or low granularity.

An example of metadata occurs within file systems. Associated with every file on the storage medium is metadata that records the date the file was created, the date it was last modified and the date the file (or indeed the metadata itself) was last accessed.

See also:

• Computers: Internet: On the Web: Syndication and Feeds: RSS: Specifications: RSS 2.0 Modules (4)

• mod_threading
  groups.yahoo.com
  An RSS1.0 module that provides the ability for items to specify a parent/child relationship.
• mod_syndication
  web.resource.org
  The RSS1.0 Syndication module provides syndication hints to aggregators and others feed regarding how often it is updated.
• mod_dublincore
  web.resource.org
  The Dublin Core module allows unqualified Dublin Core metadata to be added to RSS channels and/or items.