What is DOI?
DOI or digital object identifier is an alphanumeric tag given to a piece of intellectual property. It is a name given by the IDF or International DOI Foundation to identify any digital item on the internet. The DOI name of a particular digital object contains current information and links to its particular location on the internet.

Under the IDF, the DOI system allows for object identification and management of metadata and intellectual property. E-commerce has also benefited from the system through the linkages between the customer and suppliers. DOI names are somewhat like barcodes for digital content. It differs from URL which only points the location or address of the content. DOI meanwhile pertains to the content or object itself directly.

DOI names can be used to identify text, image, audio, software files or any file with intellectual property. DOI names start with the number 10, and contains a prefix and a suffix. Prefixes are unique characters intended for organizations and the suffixes are given by registrants. Before somebody can have a DOI name, he/she must first register with Registration Agencies (RAs). These agencies offer their services for specific sectors or communities.

Today there are already millions of registered DOI names, mostly from the printing and publishing industries. The DOI system was originally implemented for text objects or entities, but is applicable also to other media. The system also offers several functionalities. Aside from the persistent DOI name or tag, there is interoperability between data sources. New features and services can also be added through management of DOI names. It also allows for dynamic updating of metadata, services, and applications.

DOI names or tags can be put anywhere. It may be shown and be very obvious to the user or may be hidden within the digital object. In electronic articles for example, DOI names are usually located near the copyright notice. Others also may opt to have the DOI name somewhat hidden in a hyperlink.