The Digital Object Identifier (DOI) is a system for identifying content objects in the digital environment. DOIs are names assigned to any entity for use on digital networks. They are used to provide current information, including where they (or information about them) can be found on the Internet. Information about a digital object may change over time, including where to find it, but its DOI will not change. The DOI system provides a framework for persistent identification, managing intellectual content, managing metadata, linking customers with content suppliers, facilitating electronic commerce, and enabling automated management of media. DOIs can be used for any form of management of any data, whether commercial or non-commercial. The system is managed by the International DOI Foundation, an open membership consortium including both commercial and non-commercial partners, and has recently been accepted for standardisation within ISO. Several million DOIs have been assigned by DOI Registration Agencies in the US, Australasia, and Europe. Using DOIs as identifiers makes managing intellectual property in a networked environment much easier and more convenient, and allows the construction of automated services and transactions. This has been added to eCommerce Resources Subject Tracer™ Information Blog and Deep Web Research Subject Tracer™ Information Blog.