1. A system for clustering documents, the system comprising: a document vector generator operable to generate a document vector for each of a plurality of documents of a corpus; a reference vector generator operable to generate a plurality of reference vectors; a comparator operable to compare the document vectors to each of the reference vectors to generate similarity values for each of the document vectors; a sorter operable to sort the document vectors based on the similarity values for the document vectors to form a sorted list; and a cluster generator operable to form clusters of documents based on the similarity between adjacent document vectors in the sorted list.