40. A search engine as claimed in claim 38 or 39 , including a cluster for processing indices output by said index network in response to said query, generating term frequency vectors for data indexed by said indices, comparing similarities between the indexed data on the basis of a distance between said frequency vectors and generating content based categories on the basis of said distances and placing the output indices into said categories for display.
40. A search engine as claimed in claim 38 or 39 , including a cluster for processing indices output by said index network in response to said query, generating term frequency vectors for data indexed by said indices, comparing similarities between the indexed data on the basis of a distance between said frequency vectors and generating content based categories on the basis of said distances and placing the output indices into said categories for display. 42. A search engine as claimed in claim 40 , wherein said cluster generates a plurality of clusters of the indices and determines the quality of each cluster on the basis of inter-cluster distances and intra-cluster distances between term frequency vectors for the indices of the clusters relative to a term frequency vector centroid for each cluster.