DCMI Generic Namespace Policy for RDF Vocabularies

RDF vocabularies require:

• Use of URIs. Each term (e.g., property or class) in an RDF vocabulary must be identified with a URI.
• Stable identifiers. Each term URI should refer to the same term in perpetuity and should not be repurposed, sold, or forfeited through neglect (e.g., by non-payment of domain name fees). This commitment should be backed by institutional guarantees. Note that stable URIs (such as PURLs) do not automatically refer to stable documentation (such as content to which PURLs are redirected).
• Machine-processable documentation. Each term URI should remain resolvable to a machine-processable expression of its semantics in accordance with principles of Web architecture. As of 2011, such expressions include RDF schemas and OWL ontologies and are documented in forms ranging from stand-alone schema files to formal representations embedded in Web pages.
• Change policies. The stability of the meaning of the terms should be determinable -- i.e., the meanings of terms should evolve according to known change management policies and with responsibility for changes traceable to individuals or organizations. Change histories should also be published so that a vocabulary's evolution over time is a matter of public record.
• Open access provisions. Vocabularies should be made available for public access under the terms of copyright models that encourage re-use and collaboration and with well-defined mechanisms for community feedback.
• Preservation provisions. As for any other artifact of cultural and historical significance, arrangements should be made for the long-term preservation of a vocabulary.

Subscribers to these principles

• FOAF Project
• Dublin Core™ Metadata Initiative