13. The method of claim 1 , wherein the one or more past queries include a plurality of past queries.
13. The method of claim 1 , wherein the one or more past queries include a plurality of past queries. 14. The method of claim 13 , further comprising: determining whether the past queries are part of an on-topic query session; wherein ranking the given candidate query suggestion based on the comparison of the current entity collections that match the past entity collections to the current entity collections of the group only occurs if the past queries are determined to be part of an on-topic query session.