Digital object identifier
In computing, a Digital Object Identifier or DOI is a persistent identifier or handleused to uniquely identify objects. An implementation of the Handle System and standardized by the ISO, DOIs are in wide use mainly to identify academic, professional, and government information, such as journal articles, research reports and data sets, and official publications though they can be used to identify other objects, such as commercial videos.
DOI means "digital identifier of an object" rather than "identifier of a digital object". Thus DOI stands for "digital object-identifier" rather than "digital-object identifier".
Metadata about the object is stored in association with the DOI name. It may include a location, such as a URL, indicating where the object can be found. The DOI for a document remains fixed over the lifetime of the document, whereas its location and other metadata may change. Referring to an online document by its DOI provides more stable linking than simply using its URL, because if its URL changes, the publisher only needs to update the metadata for the DOI to link to the new URL.
A DOI name differs from standard identifier registries such as the ISBN and ISRC. The purpose of an identifier registry is to manage a given collection of identifiers, whereas the primary purpose of the DOI system is to make a collection of identifiers actionable and interoperable.
The DOI system began in 2000 and is managed by the International DOI Foundation. Organizations that meet the contractual obligations of the DOI system and are willing to pay to become a member of the system can assign DOIs. The DOI system is implemented through a federation of registration agencies coordinated by the International DOI Foundation, which developed and controls the system. The DOI system has been developed and implemented in a range of publishing applications since 2000; by late April 2011 more than 50 million DOI names had been assigned by some 4000 organizations. By April 2013 this number had grown to 85 million DOI names assigned through 9500 organizations.