Uldis Bojars has written a SIOC exporter plugin for WordPress 1.5+. This allows the production of SIOC metadata from your weblog.
The plugin can be found at http://sw.deri.org/svn/sw/2005/08/sioc/wordpress/
To install save plugin files [sioc.php + sioc-include.php] to the WordPress plugin directory (located in ./wp-content/plugins) and enable this plugin in the Admin->Plugins menu.
Data created by plugin can be accessed by following autodiscovery links that are added to the blog's main page and all blog posts. Main SIOC page can be found at your.host.here/wordpress-folder/?sioc_type=site.
Semantic Radar and SIOC
You may use Semantic Radar to detect presence of SIOC data on web pages. It is a Firefox extension that detects links to RDF metadata (SIOC, FOAF, DOAP, ...) and informs about them via a browser status bar icon. Clicking on the icon will provide a user-friendly view of RDF data.
News: Content negotiation added (in v1.21).
Point RDF content regotiation aware tool such as Tabulator to a blog post and it will get back RDF data, avoiding the need to find and follow autodiscovery links in HTML.