15. The method of claim 1 , wherein the items include movie titles rented by users.
1. A computer-implemented data mining method, comprising: storing, in an electronic data repository, user activity data associated with each of a plurality of users of an online 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; programmatically identifying, among the plurality of users, a subset of users whose email addresses are associated with a particular organization; programmatically analyzing the user activity data associated with the plurality of users, including the subset of users, by execution of code by a computer processor, to identify 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 creating, in computer storage, an association between the organization and the identified set of items.