7. The method of claim 1 , wherein the characteristic indexes are SimHashes.
7. The method of claim 1 , wherein the characteristic indexes are SimHashes. 8. The method of claim 7 , wherein the determining whether the first web document and the second web document are similar to each other comprises determining the first web document and the second web document as similar documents if a hamming distance between the SimHashes is equal to or below a reference numerical value.