Eric Vitiello's relationship schema has a new home at http://purl.org/vocab/relationship/

Eric and I have been working together over the last few weeks to update this popular schema. We've fixed some issues and expanded the vocabulary to incorporate many terms in use by the social network engines. The main improvements are:

• A stable namespace for the terms in the schema: http://purl.org/vocab/relationship/
• A more comprehensive RDF schema incorporating appropriate OWL constructs such as symmetric and transitive properties.
• RDF and HTML representations for all individual terms in schema, e.g. http://purl.org/vocab/relationship/friendOf
• Many new properties to cover professional, personal and genealogical relationships.
• Examples of usage with FOAF and (X)HTML

The (X)HTML examples are quite interesting since they allow relationships to be asserted between the authors of pages using rel and rev attributes on links. This is similar to the XFN method but has the advantage of having an RDF interpretation and use of a unified vocabulary.