19. The method as recited in claim 17 , further comprising determining one or more stop words from the product title; and filtering the one or more stop words from the product title, the one or more words in the product title including none of the one or more stop words.
19. The method as recited in claim 17 , further comprising determining one or more stop words from the product title; and filtering the one or more stop words from the product title, the one or more words in the product title including none of the one or more stop words. 20. The method as recited in claim 19 , wherein the determining one or more stop words from the product title comprises: determining a distribution entropy of a word under multiple categories; determining that the word is a stop word when the distribution of the word is higher than a threshold for stop word; and adding the word into a table of stop words.