6. The method of claim 5 wherein selecting the meaningful phrases includes: computing a phrase weight for each candidate phrase, the phrase weight being based on a number of documents in the corpus that contain the candidate phrase; and selecting the meaningful phrases based on the phrase weights.
5. The method of claim 1 further comprising: constructing, by the processor, a document vector for each of a plurality of documents from the corpus, the document vector including a first plurality of components corresponding to words and a second plurality of components corresponding to at least some of the meaningful phrases; and forming, by the processor, a plurality of clusters of documents based at least in part on the document vectors.