A digital magazine identifies content items for recommendation to a user by determining the address information of one or more content items. The address information of a content item identifies a source from which the content item was received and additional information describing the content item. Representations of content items are generated from the address information for each content item. Additionally, representations of content items previously presented to the user are generated from the address information for the previously presented content items. A measure of similarity between a representation of a content item and a representation of a previously presented content item is determined and used to select content items to present to the user.