1. A method for document categorization, comprising: identifying terms occurring in a collection of documents; determining a cohesion score for each of the terms, the cohesion score is a function of a cosine difference between each of the documents containing the term and a centroid of all the documents containing the term; sorting the terms based on the cohesion scores; creating categories based on the cohesion scores of the terms, wherein each of the categories includes only documents (i) containing a selected one of the terms and (ii) that have not already been assigned to a category; and moving each of the documents to a category of a nearest centroid, thereby refining the categories.