In February, DCMI and the FOAF Project agreed in principle to tighten the alignment between DCMI Metadata Terms and the FOAF (Friend of a Friend) Vocabulary specifications. FOAF and DCMI Metadata terms are often used together in applications, and both are consistently listed among the top ten vocabularies Linked Data space.
The agreement between DCMI and the FOAF Project will include a commitment to share preservation and long-term maintenance responsibilities for FOAF's xmlns.com domain name. Finalization of the agreement will involve formulating a generic namespace policy, based on the DCMI Namespace Policy (but simpler), to which both organizations can subscribe. This policy will be developed in the new DCMI wiki and is intended to be a living document that could evolve if other vocabulary maintainers were to subscribe to its principles.
Concrete benefits from closer cooperation between FOAF and DCMI could include explicit alignments between the vocabularies, building on first-step formal declaration "dct:creator owl:equivalentProperty foaf:maker". The proliferation of similar properties and classes with overlapping, partially overlapping, or perhaps only apparently overlapping semantics is a general problem that threatens the potential interoperability gains from the Linked Data approach, and a push to declare explicit alignments could serve as a high-profile example of what needs to be done.
If the future of Linked Data vocabularies is to be secured such that their documentation -- and the meaning of data that use them -- are to remain accessible twenty years from now, vocabulary maintainers will need to consider longer-term issues and scenarios such as those addressed in this specific agreement. The agreement is intended in part to raise awareness of the importance of longer-term planning. With interest from vocabularies, this agreement could represent the first step towards a farther-reaching support network among vocabulary maintainers.