A social networking system aggregates two or more stories having at least one common characteristic to create an aggregated story unit. Each story describes an action performed on an object over the social networking system or external to the social networking system. The aggregated story unit includes one or more input elements allowing a viewing user to interact with the aggregate story unit as a whole or with individual stories in the aggregated story unit. The input elements included in the aggregated story unit may be based on the types of the actions or of the objects described by stories in the aggregated story unit and on one or more input policies.