27. The system of claim 26 , wherein receiving the candidate synonym for the query phrase comprises: gathering switching data from previous queries; wherein switching data from previous queries indicates how users have switched query terms and/or query phrases when modifying queries to improve query results; and using the switching data to identify candidate synonyms for query terms and query phrases.
27. The system of claim 26 , wherein receiving the candidate synonym for the query phrase comprises: gathering switching data from previous queries; wherein switching data from previous queries indicates how users have switched query terms and/or query phrases when modifying queries to improve query results; and using the switching data to identify candidate synonyms for query terms and query phrases. 28. The system of claim 27 , wherein gathering switching data from previous queries comprises: identifying possible query phrases from the previous queries; and generating probabilities of switching between query phrases based on patterns observed in the previous queries; wherein the switching probabilities are used to determine whether a switched query phrase will be considered as a candidate synonym for a query phrase.