Update: It seems, SemaWorx is going to face some stiff competition… Their new developer app Yahoo!Pipes can possibly generate services like the ones we are going to provide to consumers. This could easily become the first killer-tool for creating Semantic Web mashups.
After having known about some of their earlier experiments with using namespaces for tagging, I read on the O’Reilly Radar, that Flickr just introduced what they call machine tags.
Those also could easily have been standards-compliant RDF/XML statements (if they just minded adding some angled brackets… ) to simplify repurposing and distribution e.g. via RSS feeds — just the way we use them for SemaWorx’ information matching.
Though their – on no account less complex – approach may start fostering wider adoption than the original did.