18. The system of claim 17 wherein the program module is further operative for: generating a concept vector for each concept data object in the concept set, the concept vector comprising a dimension for each term data object associated with the concept data object, a magnitude of the dimension based on a weight of the association of the term data object with the concept data object; and generating a document vector for the at least one returned document, the document vector comprising a dimension for each of a plurality of terms in the document, a magnitude of the dimension based on a frequency of occurrence of each of the plurality of terms; wherein evaluating the similarity between the at least one returned document and the at least one concept is based on a fuzzy membership score determined by comparing the concept vector to the document vector.
18. The system of claim 17 wherein the program module is further operative for: generating a concept vector for each concept data object in the concept set, the concept vector comprising a dimension for each term data object associated with the concept data object, a magnitude of the dimension based on a weight of the association of the term data object with the concept data object; and generating a document vector for the at least one returned document, the document vector comprising a dimension for each of a plurality of terms in the document, a magnitude of the dimension based on a frequency of occurrence of each of the plurality of terms; wherein evaluating the similarity between the at least one returned document and the at least one concept is based on a fuzzy membership score determined by comparing the concept vector to the document vector. 21. The system of claim 18 wherein the returned documents of the search results are ordered in a list and wherein the at least one returned document is displayed in a first portion of the list of returned documents and simultaneously displayed in a second portion of the list of returned documents on a display screen, and wherein the member of returned documents displayed in the second portion is greater than the number of returned documents displayed in the first portion.