• Definition from Wiki (edited)

Metadata is data that describes data. (E.g. HTML tags, EXIF details for a digital photograph) An item of metadata may describe an individual datum, or content item, or a collection of data including multiple content items.

Metadata (sometimes written ‘meta data’) is used to facilitate the understanding, use and management of data. The metadata required for effective data management varies with the type of data and context of use. In a library, where the data is the content of the titles stocked, metadata about a title would typically include a description of the content, the author, the publication date and the physical location. In the context of a camera, where the data is the photographic image, metadata would typically include the date the photograph was taken and details of the camera settings. In the context of an information system, where the data is the content of the computer files, metadata about an individual data item would typically include the name of the field and its length. Metadata about a collection of data items, a computer file, might typically include the name of the file, the type of file and the name of the data administrator.

Metatags are an example of metadata. They provide certain information about HTML files, such as keywords, desccription and the language. Such tags are used for instance by by search engines that read them in order to locate information on the Internet with greater speed.

Examples of the most frequently used metatags are:

• <meta name=”keywords” content=”[list of keywords relating to the HTML file]”/>;
• <meta name=”description” content=”[a short description of the HTML file]”/>;
• <meta name=”generator” content=”[the name and version of the software used to generate the HTML file, for instance ‘Dreamweaver MX 2004’ or ‘Frontpage 2003’]”/>;
• <meta name=”language” content=”[language in which the contents is written, for instance ‘English’ or ‘French’]”/>; and
• <meta name=”author” content=”[name of the author of the HTML file]”/>.

The list below are examples of metadata found on websites:

• UNSW Meta Description: “The University of New South Wales, located in Sydney Australia, is one of Australia’s largest and leading universities. This WWW site has a wide range of comprehensive information about the University, course offered, its activities, aims and objectives”
• UNSW Meta Keywords: “University, Information, Education, Tertiary, Sydney, Australia, Research, Study, undergraduate, postgraduate, graduate school, science, arts, technology, university of new south wales, UNSW, university of NSW, new south wales university, NSW university, university new south wales, new south wales, wales, Australia university, Australian university, university NSW, uni of NSW, uni nsw, university, unsw, universities of Australia, Sydney universities, universities Sydney, universities Sydney Australia”
• Uninotes.com.au Meta Generator: “MSHTML 6.00.2800.1458”

• Wikipedia's article on metadata
• An Introduction to Metadata