Together with Morten Frederiksen and Dan Brickley (who is revisiting his SparqlPress idea), I've created a WordPress extension (called "RDF Tools") that adds an (ARC-based) RDF Store and SPARQL Endpoint to the blogging system. The store is kept separate from the WP tables (i.e. it's not a wrapper), but you can use WP's nice admin screens to configure it (screenshot), and given the amount of developer-friendly hooks that WP offers, I'm curious what can be done now, possibly in combination with other extensions such as those Alexandre Passant is working on. It could perhaps also be handy as a deployment accelerator for knowee.