Jonathan Luster has released his Y! Terms Extraction Plugin for WordPress. It uses the Yahoo services to extract relevant keywords from a posting text and presents them as Technorati tags in the post. If anyone tries this out: I would be interested to know how well it works with German texts.
By the way, I would also be interested to know when blogg.de offers an API. I mean, it's about time to catch up with the features of Technorati and Yahoo, right?