This disclosure relates to determining whether to include items in a feed to a referral network site. A catalog is maintained of a plurality of items sold through an electronic commerce network site, wherein at least a portion of a plurality of sales of the items originate by virtue of a referral from a referral network site. A quantity of commercial data associated with the items is stored in a data store, and a predictive model is trained with the commercial data associated with the items. Each of the items is applied to the predictive model to determine whether such items are to be included in a feed to the referral network site. The feed that includes a subset of the items is sent to the referral network site.