14. The computer readable medium of claim 13 , wherein at least one of the initial relevance weights associated with an item of the plurality of items is based on a relative measure of a likelihood that the item is desired by the user.
13. A computer readable medium comprising program instructions for presenting a collection of items in which the presentation is ordered at least in part based on navigation and selection behavior of a user learned over time, wherein execution of the program instructions by a computer system causes the computer system to: provide access to a set of items; associate an initial relevance weight with each of a plurality of the items of the set; receive input entered by the user for identifying desired items; in response to the input entered by the user, select and present a subset of items to the user in a first presentation order of items browsable by the user wherein the arrangement of the items within the first presentation order is based at least in part on the initial associated relevance weights associated with the items; receive input entered by the user for browsing through the first presentation order of items and for identifying and selecting the desired items; in response to a selection by the user of an item, present said item to the user and adjust the associated relevance weight of said item; subsequent to adjusting the associated relevance weight of any of the items, select and present a subset of items to the user in a second presentation order of items browsable by the user wherein the arrangement of the items within the second presentation order is based at least in part on the adjusted associated relevance weights assigned to the items.