The first one is quite similar to the tagcloud feature (which creates a tagcloud of topics, as Technorati does but using
sioc:topic property to get topics / categories): it displays a 3D pie of the ten most popular topics, using the PHP/SWF Charts API.
The second one uses the user aspect of SIOC. It has recently been decided to use both foaf:Person and sioc:User to represent creator of a sioc:Post when exporting data, while using only FOAF for unregistered users (i.e. comments on most weblog engines). This means that every Post (whether is it an original post or a reply) is linked to a foaf:User. Then, we can create mappings and relationships between posts and users, eventually smushing data using foaf:mbox_sha1sum if users use different nicknames but same e-mail in different blogs. So, this second query displays relationships beetween users within a set of decentralized SIOC-ed blogs that have been put in the same store. Two users are connected as soon as one replied to another, providing a way to discover people you’ve got in common (sometimes without knowing it !). The Prefuse API have been used to draw the network.
This FOAF/SIOC feature that links users to post have been recently introduced in exporters (WordPress, DotClear, b2evo) and in the PHP API. So, if you use an old version of one of this exporter, update it! These new versions also provide mappings between SIOC, FOAF and DC, and removed depracates some properties (see latest ontology specs). At the moment, I only store blogs that use the latest exporters in the store, so that all of them will be taken into accout in browsing interfaces, as the SPARQL queries refer to latest specs.
Finally, some of these exporting and browsing features will be presented in an upcoming talk at BlogTalk Reloaded, with the paper “SIOC Browser – Towards a Richer Blog Browsing Experience” co-written with John Breslin and Uldis Bojars. I’ll also be involved in a talk for the paper “Folksonomies, Ontologies and Corporate Blogging”, co-written with Philippe Laublet and Jean-David Sta, introducing an approach – using SIOC – that mix folksonomies and ontologies I dealt with in my PhD work.
So, once again, don’t hesitate to use SIOC exporters on your blog / forums if available (or write one with the API !) and get listed here !