1. A computer-implemented method for displaying information related to items categorized into a plurality of nodes logically arranged into a hierarchy, each item having at least one attribute associated with the item, the method comprising: under control of instructions that are executed by one or more computing devices in a computer system: receiving a request for a first node in the hierarchy, wherein a first set of attributes is associated with the first node, and wherein each attribute is common to the items categorized in the first node; in response to receiving the request for the first node, generating display information for one or more items categorized in the first node together with at least one attribute of the first set of attributes; receiving a request for a second node in the hierarchy, the second node being a child of the first node, wherein a second set of attributes is associated with the second node, and wherein each attribute of the second set is common to the items categorized in the second node; in response to receiving the request for the second node, generating display information for one or more items categorized in the second node together with at least one attribute of the second set of attributes and at least one attribute of the first set of attributes; receiving a request for an n th node in the hierarchy, the n th node being a child of an n−1 th node, wherein an n th set of attributes is associated with the n th node, and wherein each attribute of the n th set is common to the items categorized in the n th node; in response to receiving a request for the n th node, generating display information for one or more items categorized in the n th node together with at least one attribute of the n th set of attributes, at least one attribute of the second set of attributes, and at least one attribute of the first set of attributes; and for each node, displaying a list of selectable attributes arranged into attribute categories, each attribute category including a plurality of attributes associated with the category; and in response to a selection of at least one attribute from an attribute category, adding to the list of selectable attributes at least one additional attribute category, wherein the at least one additional category is associated with the attribute category from which the at least one attribute was selected, and generating display information only for items associated with the at least one attribute that was selected, the display information including attributes associated with the at least one additional category, wherein when two or more attributes are selected from the attribute category, the attribute category is included in the display information, and when only one attribute is selected from the attribute category, the attribute category is excluded from the display information.