17. The computer program product of claim 15 , wherein the one or more subjects comprise multiple subjects, and wherein the program instructions for collecting reduce the number of the one or more electronic documents according to values of the subject-determining-power scores for the multiple subjects to refine the response to the request.
15. A computer program product comprising a computer-readable storage device storing program instructions for organizing a collection of electronic documents, wherein the program instructions comprise program instructions for: in a computer system, storing entries in multiple dictionaries separate from and not associated with any particular one of the electronic documents, wherein the multiple dictionaries are data structures within the computer system, wherein individual ones of the multiple dictionaries correspond to one of a plurality of different subjects, wherein the entries contain a descriptive term and a subject-determining-power score corresponding to the descriptive term, wherein an individual subject-determining-power score indicates the relative strength or weakness of the corresponding descriptive term with respect to the subject of the one of the multiple dictionaries containing the entry in which the descriptive term is stored, and wherein at least some of the descriptive terms are present in two or more of the multiple dictionaries; responsive to requests within the computer system to identify one or more of the electronic documents, wherein the requests include at least one search term descriptive of the one or more electronic documents, accessing the collection of electronic documents by matching the at least one search term with descriptive terms in the multiple dictionaries to determine one or more subjects of the request from subjects of one or more of the multiple dictionaries that contain the descriptive terms matching the at least one search term, and applying the subject-determining power scores to determine which of the subjects of the one or more of the multiple dictionaries that contain the descriptive terms that match the at least one search term are most applicable to the request; ranking the one or more subjects determined by the matching according to a match score computed for individual ones of the one or more subjects with respect to the at least one search term; determining one of the at least one search term having a greatest subject-determining power score among the one or more subjects and a subject to which the greatest subject-determining power score corresponds; until a predetermined number of documents are identified, collecting document tags having a best match to the highest-ranking subject for which the document tags have not yet been collected, in a collected set of document tags for the request by first collecting a number of document tags having highest subject-match scores for the subject to which the greatest subject-determining power score for a first one of the at least one search term corresponds, and adding the collected number of document tags to the collected set of document tags, second collecting another number of documents having highest subject-match scores for another subject to which a next greatest subject-determining power score for another one of the at least one search term corresponds, and adding documents from the other number of documents to the collected set of documents; reducing the collected set of document tags by retaining document tags collected by the first and second collecting according to their subject-match scores; and storing a representation of the collected set of document tags that identify the electronic documents in a memory of the computer system to provide the response to the request to identify the one or more electronic documents.