3. The method of claim 2 wherein a plurality of nodes are placeholder nodes and wherein a weight may be assigned to a placeholder node but no keywords or concepts are associated with a placeholder node.
2. The method of claim 1 wherein weights are assigned to a plurality of nodes in the controlled vocabulary and wherein the search weight for a related concept is further based on at least one weight assigned to a node in the path from the node that corresponds to the related concept to the concept node that corresponds to the assigned keyword.