1. A system for scoring concepts in a document set, comprising: a database to maintain a set of documents; a concept identification module to identify concepts comprising two or more terms extracted from the document set and to designate each document having one or more of the concepts as a candidate seed document; a scoring module to calculate a score for each of the concepts identified within each candidate seed document based on a frequency of occurrence, concept weight, structural weight, and corpus weight; a vector module to form a vector for each candidate seed document comprising the concepts located in that candidate seed document and the associated concept scores; a document comparison module to compare the vector for each candidate seed document with a center of one or more clusters each comprising thematically-related documents and to select at least one of the candidate seed documents that is sufficiently distinct from the other candidate seed documents as a seed document for a new cluster; and a clustering module to place each of the unselected candidate seed documents into one of the clusters having a most similar cluster center.