A technique for determining the impact of multiple users' actions is described. According to this technique, information specifying multiple users' actions is aggregated. This information includes linkages that indicate the initiators of the multiple users' actions. Then, the impacts of the multiple users' actions are determined based on the aggregated information. In particular, the impact of a given user's action includes a direct component performed by the given user and an indirect component performed by other users in a social graph in response to the given user's action, where the social graph includes relationships between the other users and the given user. For example, the multiple users' actions and the social graph may be associated with a website, and the determined impacts may allow traffic and/or revenue of the website to be increased.