19. A method implemented by one or more computer processors, the method comprising: receiving an input that specifies a particular semantic graph of user utterances that is based on a linguistic analysis; processing a corpus that is a historical log of user utterances, the processing performed using the specified semantic graph of user utterances and one or more other semantic graphs of user utterances that are part of semantic clusters that are formed for like topics; and outputting a result of the processing in a user interface.
22. A method as described in claim 19 , wherein the processing is performed using by taking a ratio of aggregate specificity of semantic objects that are common to two semantic graphs that are compared to an aggregate specificity of at least two semantic objects found in both of the two semantic graphs.