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 āPlanet Pingā 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.
It does now parse the category (and dc:subject) elements from the feed and also looks for technorati style tags in the content and puts them into the database.
You can now display all posts with a certain tag, for example all posts tagged āappleā. And you can also combine tags with a + which gives you all posts tagged āappleā and āintelā.
If more people apply meaningful tagging to their posts, this could become very useful. For example, if you review a movie, tag it with āmovieā and āreviewā, if it's for āKing Kongā, tag it also with ākingkongā. Now others could check out all recent movie reviews at http://all.planet.chregu.tv/tag/movie+review and all King Kong reviews at http://all.planet.chregu.tv/tag/movie+review+kingkong. The same for politic related matters, eg. āelections2006+zurichā for all elections related posts, which take part this february in zurich. The possibilities are endless. The only problem is, that bloggers should use more or less the same tags for the same topic (I can make the tag support in the planet a little bit smarter, but that's limited to some extend). Maybe some sort of guidelines about which tags should be used for what could be in order to make this service way more useful.
BTW, if you want to be sure to be on āPlanet Pingā, just ping http://ping.blogug.ch/ from your blogging tool (most blogging tools have an option for that) and new posts will show up there within 1 or 2 minutes. Otherwise ping.blogug.ch will check every hour for new posts and send them to Planet Ping (but only, if your posts have a date, which surprisingly only about 480 out of 780 blogs from list.blogug.ch have. Not true, error in my scriptā¦).