1. A computer-implemented method for updating phrases associated with a limited document collection, comprising: determining, by at least one processor of a computer system, a list of top phrases for the limited document collection, at least in part based on presence, in documents of the document collection, of both the top phrases and related phrases of the top phrases; receiving, by at least one processor of the computer system, a replacement phrase for at least one of the top phrases; and updating, by at least one processor of the computer system, related phrase data for the replacement phrase from the related phrase data of the top phrase that is being replaced.