14. A web query refinement method comprising the following computer-implemented acts: receiving a search query; navigating a search domain classified by a topic hierarchy or a topic cluster based on the search query; inferring items of interest by generating a series of one or more questions and receiving answers to the series of one or more questions from a particular user; modifying a heuristic rule pertaining to the search domain classified by the topic hierarchy or the topic cluster based at least on knowledge learned from inferring the items of interest using the answers received from the particular user for the series of one or more questions to generate a modified heuristic rule; and modifying the search query to generate a modified search query based at least on the items of interest, the modified heuristic rule, and a navigated position in the topic hierarchy or the topic cluster.
14. A web query refinement method comprising the following computer-implemented acts: receiving a search query; navigating a search domain classified by a topic hierarchy or a topic cluster based on the search query; inferring items of interest by generating a series of one or more questions and receiving answers to the series of one or more questions from a particular user; modifying a heuristic rule pertaining to the search domain classified by the topic hierarchy or the topic cluster based at least on knowledge learned from inferring the items of interest using the answers received from the particular user for the series of one or more questions to generate a modified heuristic rule; and modifying the search query to generate a modified search query based at least on the items of interest, the modified heuristic rule, and a navigated position in the topic hierarchy or the topic cluster. 15. The method of claim 14 , further comprising executing the modified search query to generate query results.