A social networking system provides a user with a feed of content items associated with other users connected to the user via the social networking system. Additionally, the social networking system identifies additional content items for presentation to the user and generates groups of additional content items so each group includes content items having a characteristic associated with the group. A scoring function is applied to each group to determine an expected amount of user interaction with content items in the group. Based on the expected amounts of user interaction, a featured content item is selected from each group. When a group of the additional content items is presented, the featured content item is visually distinguished from other content items in the group.