Persistent W3C Namespace

Use namespace provided by the W3C (http://www.w3.org/ns/) Can be accessed using https. Must be administrated by a W3C Community Group (CG). Both the Open Government CGand the Hydra CG come to mind.

Side effect: global visibility.

Persistence is optimal: http://www.w3.org/Consortium/Persistence.html

Even the the European Commission uses it for the ISA Programme Location Core Vocabulary: http://www.w3.org/ns/locn

That LOCN vocabulary is controlled by the Locations and Addresses Community Group: http://www.w3.org/community/locadd/