1. A method comprising, by one or more computing systems: receiving sponsor specifications designating story characteristics, wherein the story characteristics comprises an entity identifier (ID); monitoring an organic activity stream for entries matching the story characteristics; identifying an entry as matching the story characteristics at least in part because the entry is associated with a user of a social-networking system interacting through the social-networking system with an entity corresponding to the entity ID; calculating a score for each of one or more viewing users of the social-networking system, the score representing the viewing user's affinity for the user interacting through the social-networking system with the entity based at least in part on the viewing user's profile on the social-networking system; and in response to identifying an entry as matching the story characteristics, providing for display the entry in a predetermined area of a feed, the entry provided for display to one or more of the viewing users selected at least in part based on the calculated scores.