1. A method executed by one or more computing devices for characterizing a document, the method comprising: generating, by at least one of the one or more computing devices, one or more sets of taxonomic nouns corresponding to a document, wherein the one or more sets of taxonomic nouns comprise one or more of: a set of first taxonomic nouns based upon classification information generated by an author of the document; a set of second taxonomic nouns based upon one or more user-generated tags characterizing at least a portion of the document; a set of third taxonomic nouns based upon one or more search terms utilized to access the document; or a set of fourth taxonomic nouns based upon the attributes related to a method of access of the document; generating, by at least one of the one or more computing devices, a set of fifth taxonomic nouns by processing the document based upon one or more pattern rules and a dictionary of known terms, wherein the one or more pattern rules specify a method of extracting terms from the document; and aggregating, by at least one of the one or more computing devices, at least one of the one or more sets of taxonomic nouns with the set of fifth taxonomic nouns into a composite set of taxonomic nouns; and characterizing, by at least one of the one or more computing devices, the document based on the composite set of taxonomic nouns.