13. The search system described in claim 12 , wherein the covering degree of the topic representation contained in the super page of one of the multiple Web pages is a similarity degree or a difference degree concerning the topic representation between the super pages of the multiple Web pages.
15. The search system of claim 13 , and comprising a current page analyzing part that analyzes a covering degree of the topic representation that is contained in a current version of one of the multiple Web pages, wherein the re-ranking part generates a renewed page ranking to each of the multiple Web pages by comparing the analysis results obtained by the current page analyzing part between the current versions of the multiple Web pages.