A social networking system (SNS) provides sponsored stories and organic stories about actions taken by other SNS users to a viewing user. Organic stories are selected based on the likelihood the viewing user is interested in their content. While advertisers compensate the SNS for presentation of sponsored stories, the sponsored stories also include information about actions by other SNS users. To increase the likelihood the viewing user interacts with sponsored stories, a common communication channel is used to present both the sponsored stories and the organic stories. To simplify selection of organic stories and sponsored stories, the SNS determines a common unit of measurement for both and makes selections based on the common unit of measurement.