16. A computer system comprising one or more computers, said computer system programmed, via executable code stored in computer storage, to perform a method that comprises: storing, in an electronic data repository, user activity data associated with each of a plurality of users of an interactive system that provides access to an electronic catalog, said user activity data reflecting user-generated events associated with particular items represented in the electronic catalog; identifying, among the plurality of users, a subset of users whose email addresses are associated with a particular organization; analyzing the user activity data associated with the plurality of users, including the subset of users, to identify, among the items represented in the electronic catalog, a set of items that have experienced significantly higher levels of user activity among the subset of users than among the plurality of users; and storing, in computer storage, association data that associates the organization with the identified set of items.
17. The computer system of claim 16 , wherein the computer system is further programmed to use the association data to cause an association between the organization and the identified set of items to be exposed to users of the interactive system.