11. A system for determining metadata to be assigned to a document, the system comprising: at least one input interface configured to input a document to be published to a collection of documents organized according to a predetermined taxonomy that includes a stored plurality of predetermined knowledge categories, wherein the plurality of predetermined knowledge categories includes at least one controlled list of keywords; a user interface configured to permit a user to select at least one knowledge category for the document as a selected knowledge category; and a processor including: a first component configured to apply a trained text classifier to the inputted document and to output from the trained text classifier at least one of the plurality of predetermined knowledge categories as a recommended knowledge category; a second component configured to automatically present to a user the recommended knowledge category and at least one related knowledge category including at least one of a specialized related knowledge category and a generalized related knowledge category within a hierarchy of categories within the predetermined taxonomy including the at least one recommended knowledge category, wherein the user is permitted to select at least one of the recommended knowledge category and the at least one related knowledge category; and a third component configured to assign the at least one selected knowledge category as metadata for publishing the document to the collection of documents.
20. The system of claim 11 , wherein the at least one controlled list of keywords includes keywords selected by a professional organization.