20. The method of claim 14 , further comprising mapping one or more of the first plurality of documents to a knowledge sub-dimension, wherein each of the one or more documents is characterized by a subset of the one or more concepts.
20. The method of claim 14 , further comprising mapping one or more of the first plurality of documents to a knowledge sub-dimension, wherein each of the one or more documents is characterized by a subset of the one or more concepts. 23. The method of claim 20 , wherein the ordering includes ranking documents within the knowledge sub-dimension based on relevance of each document in the knowledge sub-dimension to a selected concept, wherein the selected concept is derived from a query of a particular user.