Patent ID: 8555173

Claim:
A system for determining an item to present to a first user, comprising: a processor configured to: receive preference information comprising the preferences of a plurality of users associated with one or more items; determine user correlations from the received preference information; determine, for the first user, a set of other users most correlated with the first user; and present one or more items to the first user based at least in part on preferences of the other users; and a memory coupled to the processor and configured to provide the processor with instructions; wherein determining a user correlation between the first user and a second user comprises: identifying a dugg set of items that both the first user and the second user have preferences for; identifying a buried set of items that both the first user and the second user have preferences against; identifying an exclusion set of items for which one of the first user and the second user has a preference for, and for which the other of the first user and the second user has a preference against; subtracting a size of the exclusion set from a size of a union of the dugg set and the buried set to yield a numerator; and dividing the numerator by a total number of preferences received from the first user and the second user, to yield the user correlation between the first user and the second user.