tagger

Reuters released a web service called Open Calais. It is built on <a href=''http://www.clearforest.com/">clear forest technology that has been around for a while.

You can throw text at it and get tags organized by country, personalities, industry terms, ... in RDF format back. It is of better accuracy than http://tagger.flaptor.com/findtags, http://tagthe.net or yahoo terms extraction API (http://www.programmableweb.com/api/yahoo-term-extraction, http://drupal.org/project/yahoo_terms)

You can try it here:
http://autotagger.opensynapse.net/