15. A method comprising: analyzing, by a processor in a computer system, query logs to identify a pair of queries that are the same except that a first query, in the pair of queries, includes an extra term that is not included in a second query in the pair of queries; identifying, by a processor in the computer system, whether the pair of queries is associated with a quantity of search results that are different between the pair of queries; identifying, by a processor in the computer system, the extra term as a term that is significant when the pair of queries is associated with at least a threshold quantity of search results that are different between the pair of queries; and processing, by a processor in the computer system, a query that includes the extra term based on identifying the extra term as a term that is significant.
19. The method of claim 15 , further comprising: analyzing the query logs to identify whether a user provided the first query followed by the second query; and identifying the extra term as a term that is significant when the user does not provide the first query, followed by the second query, a quantity of times that exceeds a threshold.