30. The method of claim 16 , wherein the step of receiving an original question is performed by a question and answer portal to which users submit questions for other users to answer; and the step of using the single concept set to identify questions similar to the original question comprises searching the question and answer portal to find questions, previously submitted by users, that are similar to the original question.
16. The method of claim 1 , wherein using the single concept set to determine how to respond to the original question comprises using the single concept set to identify questions similar to the original question.