In a nutshell : The DOI system is a completely self-contained system that allows to retrieve document. It is using the handle.net resolver system. The web sites that are using the Handle are running a handle server written in Java. For example, their pages contain the following locator : hdl:4263537/4080 which is a Handle but the "hdl:" protocol is not understood by your browser unless you have got a Client Resolver. However, all browsers may access to Handle documents by using a proxy server, which means you are going to have to access the hdl.handle.net server which in turns will find the standard URL for you. For example hdl:4263537/4080 will be resolved by using the hyperlink http://hdl.handle.net/4263537/4080 into http://www.handle.net/faq.html, which is the FAQs about the Handle which you are strongly encouraged to read !. The proxy acts as a bridge between two completely independent ways of retrieving documents on the Internet. The International DOI Foundation defines and manages the DOIs which are a specific class of Handles. For example 10.1037/0003-066X.59.1.29 is a DOI which can be resolved using the link http://dx.doi.org/10.1037/0003-066X.59.1.29 into an "ICANN" URL : http://content.apa.org/journals/amp/59/1/29. The DOI is using its specific proxy server : http://dx.doi.org. In a further evolution the DOI combines the Handle system and the OpenURL. The OpenURL is a misnommer, it is a context-sensitive linking system, this means that the links you are going to get are to depend on the "context" ie your authorization status within a Digital Right Management (DRM) system. The largest DOI registration agency is Crossref.org which is an organization which sells DOIs mostly to scientific publishers ( akin to a sort of registrar ). Therefore, the overall organization is layered and managed by various entities. It is quite different and somewhat more complicated that the DNS system as managed as a whole by ICANN. This very short introduction is by no means comprehensive and may contain inacurracies, only the original documents have legal and technical values.

Use of the Handle system ( independent of the DNS system ) Any production operation requires a Licence from the Corporation for National Research Initiatives ( CNRI ).

Software patent over DOI (Pat. No. 6,135,646 ) "System for uniquely and persistently identifying, managing and tracking digital objects" (10/24/00).

The International DOI Foundation (IDF) has a Licence for use of the Handle System, together with the ability to sub-license this for DOI assignment to all DOI Registration Agencies. Use of DOI therefore does not require a separate Handle System License. CNRI is not a member of the IDF but provides services to it under commercial agreements. These agreements also ensure continuity of the resolution service provided to IDF.

The Charter members of the International DOI Foundation are : Association of American Publishers, Elsevier, International Publishers Association, ,John Wiley & Sons, McGraw-Hill, Springer. Being a member of the International DOI Foundation is not free : The current annual fee for Charter Members is $US 70,000, for General Members is $US 35,000 ( that can be reduced to $US 11,500 ). The fee for Registration agencies is $US 35,000. This de facto prevents non commercial entities ( eg Open Access journals and archives ) to be members of International DOI Foundation (IDF) .

The largest DOI registration agency crossref.org is operated by Publishers International Linking Association, Inc. The Board of Directors comprises representatives from AAAS (Science), AIP, ACM, APA, Blackwell Publishers, Elsevier Science, IEEE, Kluwer, Nature, OUP, Sage, Springer, and Wiley. In order to use the services of this registration agency, publishers have to pay fees with discount for large volume users, thereby treating small publishers on an unequal basis.

The combination of the DOI and OpenURL may allow all kind of controls upon information linkage, whether ethically legitimate or not.

The International DOI Foundation (IDF) and CrossRef, currently, the main application of the DOI are all initiatives from the main commercial scientific publishers. International Organizations, Governments, and other non-profit stakeholders are not involved.