After Matthias from blog.ch added categories support for his blog list, I had the idea to extract tags per post and make them available. So, I took my semi-private "Planet Ping" project (based on the Planet PHP code and the data from list.blogug.ch resp. the pings from ping.blogug.ch) and added tag support to it.
Benjamin and I we're working on Geolocation support for Flux CMS resp. its blog plugin last week.