12. The system of claim 11 , wherein determining whether the first document is the query-specific duplicate of the second document further comprises comparing one or more first query-relevant parts of the first document and one or more second query-relevant parts of the second document, where each first query-relevant part and each second query-relevant part includes at least one of the one or more keywords.
12. The system of claim 11 , wherein determining whether the first document is the query-specific duplicate of the second document further comprises comparing one or more first query-relevant parts of the first document and one or more second query-relevant parts of the second document, where each first query-relevant part and each second query-relevant part includes at least one of the one or more keywords. 17. The system of claim 12 , wherein the one or more first query-relevant parts are a limited portion of the first document and the one or more second query-relevant parts are a limited portion of the second document.