11 months ago I posted a short entry that posed the question of whether the world needed a metadata extraction service. I stated that the service could quickly become the largest repository of metadata (in the form of named entites and facts) on the Web if it stored the resulting metadata from each request. Open Calais seems to me to be the "metadata extraction service" I had in mind; it's is a Web service that allows you to automatically annotate content and extract information like facts and named entities (people, places, and organizations, and much more) from unstructured text. If that weren't enough of a good thing, Open Calais returns the metadata in RDF.

Although the question of whether we need it still hasn't been answered, I believe this service could be a catalyst for change towards Semantic Web standards if it is integrated into (or used to create plugins for) the multitudes of open source blogs and other CMS software. Open Calais opens the door to the possibility of lowering the barrier enough for everyday users to publish semantic content.