The Permanent Document Identification

A DOI differs from other referencing systems used on the Internet, such as the URL, in that it is permanently linked to the object and not just to the location where the object is placed. Via the DOI, current and structured metadata are assigned to the document, so that when documents change their location, the DOI always remains the same and only the URL in the DOI database needs to be updated.

The DOI is also known as the "Intellectual Property Barcode". Like the printed barcode, the DOI is a distinctive identification tool throughout the supply chain and thus represents a rationalization tool.