Patent ID: 7254552

Claim:
An electronic catalog system, comprising: an electronic catalog of items that are available for purchase, the electronic catalog including pages that include descriptions of the items, and providing functionality for users to select items to purchase; a user interface through which the users can explicitly elect to expose their respective purchase histories to other users; a data repository which stores information about a plurality of groups of users, wherein each group represents a subset of a general user population, said data repository further storing preference data indicative of elections made by the users to expose their respective purchase histories to other users; and a computer system that executes a personalization component which is responsive to a request from a first user for a catalog page that includes a description of a first item, by at least (a) determining whether the first item has been purchased by a second user who belongs to a selected group of said plurality of groups, said selected group being associated with the first user, and (b) in response to detecting that the first item has been purchased by the second user, notifying the first user during browsing of the electronic catalog that the first item has been purchased by the second user, wherein the personalization component uses said preference data to determine whether, and to whom, a given purchase is to be exposed.