This cropped up in yesterday’s W3C Semantic Web Coordination Group telecon, as we discussed the various measures of SKOS deployment success.
I suggested drawing a distinction between the use of SKOS to publish thesauri (ie. SKOS schemes), and the use of SKOS in RDFS/OWL schemas, for example subclassing of skos:Concept or defining properties whose range or domain are skos:Concept. A full treatment would look for a variety of constructs (eg. new properties that declare themselves subPropertyOf something in SKOS).
An example of such a use of SKOS is the new sioc:Category class, recently added to the SIOC namespace.
Here are some quick experiments with Sindice.
Here’s a query that finds all mentions of skos:Concept in an object role within an RDF statement:
This all seems quite healthy, although I’ve not clicked through to explore many of these results yet.
BTW I also tried using the proposed (but retracted – see CR request notes) new SKOS namespace,
http://www.w3.org/2008/05/skos#Concept (unless I’m mistaken). I couldn’t find any data in Sindice yet that was using this namespace.