I've just started looking at Open Calais. I used it to tag a few documents. One issue is that my application is for a semantic Cognitive Science portal. To provide a tool for researchers to do semantic searches on various researchers, topics, etc. For example "find documents that disagree with the blank slate empiricist hypothesis" which would return things like Steven Pinker's book The Blank Slate. Many of the tags are business focused and aren't very relevant to what I want to do. At the same time I want to provide a lot more depth in the Science tags, not just things like Computer Science or Linguistics but hierarchies such as Linguistics>Computational Linguistics>X Bar Theory. I have a lot of experience developing OWL ontologies with Protege, is it possible for me to upload my own ontology? Or are there other ways for me to customize the tags?