1. A computer-implemented software tool for training and testing a knowledge base of a computerized customer relationship management system, comprising: corpus editing processes, performed on one or more computers, for displaying and editing corpus items belonging to a corpus, and for assigning a suitable category from a set of predefined categories to individual corpus items; knowledge base building processes, performed on the one or more computers, for building a knowledge base of a computerized customer relationship management system by performing natural language and semantic analysis of a first subset of the corpus items and thereby deriving semantic and statistical information from the corpus items that are associated with nodes in the knowledge base; knowledge base testing processes, performed on the one or more computers, for testing the knowledge base of the computerized customer relationship management system on a second subset of the corpus items by extracting concepts from the corpus items of the second subset, performing statistical pattern matching to generate a set of match scores for each corpus item of the second subset, wherein each match score in the match score set represents a confidence level for classifying each corpus item of the second subset into at least one of the predefined categories using the semantic and statistical information associated with the nodes in the knowledge base of the computerized customer relationship management system; and reporting processes, performed on the one or more computers, for generating reports based on results produced by the knowledge base testing processes and causing the reports to be displayed to a user of the computerized customer relationship management system to gauge performance of the knowledge base, so that appropriate adjustments are made to improve the performance of the knowledge base.