Abstract: A social marketing system may measure the performance of marketing campaigns using the effective click through rates that include impressions that are due to propagation of items through social networks. A social marketing system may track an initial effectiveness in starting a campaign, as well as track the propagation of the campaign information through multiple social networks. The effectiveness of the campaign may be measured using the effective click through rates for various target audiences. The social marketing system may create links to advertising materials and thereby track interactions when users click through the links to interact with the materials. The effectiveness of the social media campaign may be based in part by measuring the actual or estimated number of impressions through social media networks.