6. A system for categorizing items, the system comprising: a data store adapted to store a plurality of hierarchically organized categories for items, each of the hierarchically organized categories including at least one category attribute and corresponding category attribute value; and an item categorization service in communication with the data store, the item categorization service adapted to: receive item information associated with an item of interest, the item information comprising at least one item attribute and corresponding item attribute value for the item of interest; assign a first category for the item of interest from the hierarchically organized categories stored by the data store using the item information; determine one or more rules associated with the assigned first category; identify one or more second category candidates using the one or more rules and a relevance value associated with the item information and the at least one second category candidate; determine which of the second category candidates has the most second category candidate attributes of the second category candidates; and select the second category candidate that has the most second category candidate attributes as the second category of the item of interest.
6. A system for categorizing items, the system comprising: a data store adapted to store a plurality of hierarchically organized categories for items, each of the hierarchically organized categories including at least one category attribute and corresponding category attribute value; and an item categorization service in communication with the data store, the item categorization service adapted to: receive item information associated with an item of interest, the item information comprising at least one item attribute and corresponding item attribute value for the item of interest; assign a first category for the item of interest from the hierarchically organized categories stored by the data store using the item information; determine one or more rules associated with the assigned first category; identify one or more second category candidates using the one or more rules and a relevance value associated with the item information and the at least one second category candidate; determine which of the second category candidates has the most second category candidate attributes of the second category candidates; and select the second category candidate that has the most second category candidate attributes as the second category of the item of interest. 14. The system of claim 6 , wherein the item classification service is further adapted to assign the second category of the item of interest by selecting a deepest common ancestor of hierarchically organized selected second category candidates, wherein the deepest common ancestor comprises the selected second category candidate in the hierarchically organized selected second category candidates that is common to more of the hierarchically organized selected second category candidates than any other selected second category candidate.