1. A computer-implemented method, comprising: on a server system having one or more processors that execute programs stored in the memory of the server system: collecting and storing in the memory a media item repository, a plurality of media items in the media item repository having associated classes; collecting and storing in the memory generic selection data for a plurality of users of the media item repository, the plurality of users including a particular user of the media repository; determining likelihood of a generic user selecting media items associated with particular classes; determining likelihood of the particular user selecting media items associated with the particular classes; determining relative likelihood of the particular user selecting media items associated with the particular classes compared to the generic user; and sending to the particular user a first collection of media items reflecting the relative likelihood, wherein each media item is selectable by the particular user.