1. A computer-implemented method of identifying at least one key term related to a similar passage, comprising: identifying a plurality of documents stored in a corpus, wherein each document contains an instance of the similar passage; identifying a context for each similar passage instance based, at least in part, on the document in which the similar passage instance appears; determining at least one key term related to the similar passage based on the contexts of the similar passage instances; and storing the at least one key term on a computer-readable storage medium.