(The Metadata Company, LLC, Long Beach, CA, www.metadata.com). Formerly Metadata Information Partners, Metadata is a software firm offering a variety of data management products and services. In 1986, the U.S. Patent and Trademark Office granted the company incontestable status for the Metadata trademark. Whenever the term is used generically in this encyclopedia (definition #2 below), it is spelled with a dash (meta-data).
(meta-data) Data that describes other data. For example, data dictionaries and repositories provide information about the data elements in a database (see data dictionary
). Digital cameras store meta-data in the image files that include the date the photo was taken along with camera settings (see EXIF
). Digital music files contain meta-data such as song title and artist name (see ID3 tag
). Meta-data are stored in an HTML page (Web page) to help search engines define the page properly, and most especially, make it rank higher in the results list (see meta tag
Meta-data has existed for centuries. Card catalogs and handwritten indexes are examples long before the electronic age. See Meta Data Coalition
The Most Glaring Lack of Meta-Data
The music CD should have been designed with meta-data, such as album name, artist and song titles. With 650 million bytes of storage, a few thousand could have easily been reserved for future use. In the early 1980s, readouts to display this information were expensive, and the future was not considered. The result was a circuitous route of searching by track length for the missing data on the Internet when a CD was played on the computer (see CDDB
), as well as conflicts in older stand-alone CD players when meta-data was finally added to the format.
Meta-Data in the Snowden Debacle
After former CIA employee Edward Snowden leaked top-secret American surveillance programs to the press in May 2013, meta-data came front and center. It was revealed that the U.S. National Security Agency (NSA) had undertaken massive phone surveillance, and the controversy was about what was recorded: the actual voice conversations or only the meta-data (times and telephone numbers of the calls). Even when voice content is not recorded, the meta-data can be analyzed to determine who might be in contact with suspected terrorists.
Meta-Data in an Image File
A huge amount of meta-data can be stored in an image file. The IPTC Core section (expanded below) is a meta-data standard from the International Press Telecommunications Council for adding creation data.
A Ton More
An image file can be edited to include a huge amount of meta-data to describe the file. DICOM stands for Digital Imaging and Communications in Medicine.