2. The method of claim 1 , wherein identifying a plurality of documents, comprises: for each document in the set of documents: determining term frequency scores for terms in the respective document; and ordering the terms in the respective document by term frequency score; and identifying the plurality of documents in the set of documents whose respective top N terms by term frequency score are the same.
2. The method of claim 1 , wherein identifying a plurality of documents, comprises: for each document in the set of documents: determining term frequency scores for terms in the respective document; and ordering the terms in the respective document by term frequency score; and identifying the plurality of documents in the set of documents whose respective top N terms by term frequency score are the same. 3. The method of claim 2 , wherein identifying comprises identifying a plurality of documents, from the set of documents, whose respective top N terms by term frequency score are the same and the ordering of the respective top N terms by term frequency score are the same.