How about the "tag" URI? draft-kindberg-tag-uri-02.txt This document describes the "tag" Uniform Resource Identifier (URI) scheme and the "tag" Uniform Resource Name (URN) namespace, for identifiers that are unique across space and time. Tag URIs (also known as "tags") are distinct from most other URIs in that they are intended for uses that are independent of any particular method for resource location or name resolution. A tag URI may be used purely as an entity identifier. Bill
