Update 2005-11-28: The Internet Engineering Steering Group (IESG) "approved the proposed INFO Uniform Resource Identifier (URI) scheme. As a consequence, the Internet Draft specifying the INFO URO scheme has moved to the Queue of the Internet Engineering Task Force (IETF) where it awaits formal publication as an RFC (Request for Comments [note]). INFO URI solves problems with identifying information assets, including documents and terms from classification schemes. The scheme is a consistent and reliable way to represent and reference such standard identifiers as Library of Congress Control Numbers on the Web so that these identifiers can be "read" and understood by Web applications." See the announcement "NISO-Sponsored INFO URI Scheme Gets Thumbs Up from IETF Group."

[anuary 15, 2004] An announcement from the National Information Standards Organization (NISO) describes the launch of a new INFO Registry supporting the INFO URI Scheme. Embraced by the OpenURL Framework, the INFO URI Scheme was developed within the library and publishing communities to expedite the referencing by URIs of information assets that have identifiers in public namespaces but have no representation within the URI allocation. Participants in the joint task force include the Los Alamos National Laboratory, Online Computer Library Center (OCLC), Elsevier, and Manifest Solutions; the initiative also builds on earlier consultations with representatives from the World Wide Web Consortium (W3C) and the Internet Engineering Task Force (IETF). The motivation behind developing the info URI scheme is "to allow legacy identification systems to become part of the Web global information architecture so that the information assets they identify can be referenced by Web-based description technologies such as XLink, RDF, or Topic Maps. The scheme is concerned with 'information assets', not 'digital assets' per se, so the information assets may be variously digital, physical or conceptual." The new INFO Registry is accessible online and is available for receiving new registrations. "This Registry contains all the information needed by Web applications to make use of INFO namespaces. Each Registry entry defines the namespace, the syntax, and normalization rules for the representing INFO identifiers as URIs, and gives full contact information for the namespace authority for that entry. Moreover, the INFO Registry is readable by both humans and machines alike."

From the "info" URI Scheme for Information Assets Internet Draft

There exist many information assets with identifiers in public namespaces that are not referenceable by URI schemes. Examples of such namespaces include Dewey Decimal Classifications (DEWEY), Library of Congress Control Numbers (LCCN), NISO Serial Item and Contribution Identifiers (SICI), NASA Astrophysics Data System Bibcodes (BIBCODE), and National Library of Medicine PubMed identifiers (PMID). Other candidate namespaces include Publisher Item Identifiers (PII), Online Computer Library Center OCLC Numbers (OCLCNUM), and NISO OpenURL Framework identifiers (OFI) amongst others.

The "info" URI scheme facilitates the referencing of information assets that have identifiers in such public namespaces by means of URIs. When referencing an information asset by means of its "info" URI, the asset shall be considered a "resource" as defined in RFC 2396 and shall enjoy the same common syntactic, semantic and shared language benefits that the URI presentation confers. As such, the "info" URI scheme enables public namespaces that are not part of the URI allocation to be represented within the allocation. The "info" URI scheme thus provides a bridging mechanism to allow public namespaces to become part of the URI allocation.

Namespaces declared under the "info" URI scheme are regulated by an "info" Registry mechanism. The "info" Registry allows a public namespace that is not part of the URI allocation to be declared in a registration process by the organization that manages it (the Namespace Authority). The "info" Registry supports the declaration of public namespaces that are not part of the URI allocation in a manner that facilitates the construction of URIs for information assets without imposing the burdens of independent URI registration and maintenance of resource representations on the Namespace Authority. Information assets identified within a registered namespace shall be added or deleted according to the business processes of the Namespace Authority, and yet may be referenced within network applications via the "info" URI in an open, standardized way without additional action on the part of the Namespace Authority.

The "info" URI scheme exists for identification purposes alone. Implementations must not assume that an "info" URI can be dereferenced to a representation of the resource identified by the URI. Applications of the "info" URI scheme are limited to the identification of information assets and the declaration of rules for comparing identity of such information assets regardless of whether any services relating to such information assets are accessible on the Internet... [from the v01 spec]

Overview: About "info" URIs

"info" is a shorthand for the information asset that it references by means of a URI. Another reading of info is that info exists solely to provide information about an information asset, the information disclosed being restricted to identity alone. Richer sets of information, such as authority metadata, would require resolution services which are not supported by info and hence would require a corresponding independent URI scheme or URN namespace application...

The info URI scheme does not compete with independent URI registrations but rather cooperates with independent URI registrations by providing a lightweight early URI registration mechanism to support referencing of public information assets ahead of any possible subsequent URI scheme or URN namespace application. Note that in the majority of cases no subsequent URI scheme or URN namespace application will be made by a Namespace Authority as the info resource identifier alone will be sufficient in providing an identification service. Only if additional services are required would a Namespace Authority seek to register independently...

The namespaces eligible for registration under info will typically be those of interest to the publishing, library and media communities. These communities necessarily have a very wide purview. Candidate namespaces will be those that are for public use only and that are not part of the URI allocation. Non-public namespaces are not eligible for registration. For all registered namespaces the reader is advised to consult the info Registry. The following registered namespaces are typical: bibcodes - NASA Astrophysics Data System Bibcodes; doi - International DOI Foundation Digital Object Identifiers; lccn - Library of Congress Control Numbers; oclcnum - Online Computer Library Center (OCLC) Numbers; ofi - NISO OpenURL Framework Identifiers; pmid - National Library of Medicine PubMed Identifiers; sid - Source Identifiers, as used by the OpenURL Framework.

The info Registry is publicly accessible and supports discovery (by both humans and machines) of:

• String literals identifying the namespaces
• Names and contact information of Namespace Authorities
• Syntax requirement for identifiers maintained in such namespaces
• Normalization methodology for identifiers maintained in such namespaces
• Ancillary documentation [from the FAQ document]

From the Announcement

Working under the auspices of the National Information Standards Organization (NISO), a joint task force of the publishing and library communities has developed and published a Uniform Resource Identifier (URI) scheme aimed at the identification of information assets. Information assets should be interpreted rather broadly to include, for example, documents and terms from classification schemes. The INFO URI scheme is a consistent and reliable way to represent and reference such standard identifiers as Dewey Decimal Classifications on the Web so that these identifiers can be "read" and understood by Web applications. Led by four NISO members and associates -- Los Alamos National Laboratory, Online Computer Library Center (OCLC), Elsevier, and Manifest Solutions -- the initiative builds on earlier consultations with representatives from the World Wide Web Consortium (W3C) and the Internet Engineering Task Force (IETF). An Internet-Draft for the INFO URI scheme was first published Sept. 25th, 2003 and a revision published December 5, 2003. See draft-vandesompel-info-uri-01.txt.

Herbert Van de Sompel, Digital Library Research & Prototyping at the Los Alamos National Laboratory's Research Library, stated, "A good example of the problem that the INFO URI scheme solves involves PubMed identifiers: unique numbers assigned to records in the PubMed database maintained by the National Center for Biotechnology Information (NCBI) of the National Library of Medicine. PubMed identifiers originated prior to the Web, so they are not URIs. As such they do not exist naturally in the Web infrastructure because the Web only recognizes URIs as a means to identify information resources. So Web applications cannot use PubMed identifiers, and hence cannot reference PubMed records that are identified by them. The solution is to turn PubMed identifiers into URIs. The INFO Registry enables the registration of public namespaces of standard identifiers; NCBI registered its PubMed identifier namespace under the INFO Registry -- their namespace is pmid -- so we can now talk about the record with the PubMed identifier '12376099' in URI terms as <info:pmid/12376099>."

"The goal of INFO is to act as a bridging mechanism to the Web by providing a lightweight means for registering public namespaces used for the identification of information assets," said Tony Hammond, Advanced Technology Group at Elsevier, a world-leading publisher of scientific, technical and medical information products and services. "We see INFO as an enabling technology for the library, publishing and media communities-a way to facilitate and speed the growth of the Web as a truly global information place beyond a basic document repository. The Library of Congress, the National Library of Medicine, and NASA are among those organizations that have already registered public namespaces with the INFO Registry."

"There are different ways to represent these identifiers on the Web," explained Pat Harris, NISO's Executive Director, "but the INFO URI scheme really simplifies matters. As a Web user, you aren't likely to see the scheme in action on your screen-for example, <info:lccn/2002022641>, because it's an under-the-hood way of communicating the identity of an information asset to a Web application."

"There are different ways to represent these identifiers on the Web," explained Pat Harris, NISO's Executive Director, "but the INFO URI scheme really simplifies matters. As a Web user, you aren't likely to see the scheme in action on your screen-for example, <info:lccn/2002022641>, because it's an under-the-hood way of communicating the identity of an information asset to a Web application."