Methods, systems, and apparatus, including computer programs encoded on a computer-readable storage medium, and including a method for displaying content. The method comprises receiving content items that are publishable to an activity stream in a social networking application for a user in a social network. The method further comprises evaluating the received content items using social criteria, including determining a social quality score for each content item. The method further comprises filtering the received content items to remove content items having social quality scores below a predetermined threshold. The method further comprises ranking remaining content items according to their associated social quality scores. The method further comprises publishing the remaining content items in the activity stream for the user in an order based at least in part on the ranking.