1. A method comprising: monitoring an activity stream that comprises a plurality of actions of different action types performed by users of a social networking system; storing a plurality of sponsored story specifications that each designates at least one action type to be included in a sponsored story; identifying, in the monitored activity stream, at least one action performed by a subject user, the at least one action matching an action type specified in one or more of the plurality of stored sponsored story specifications; for each of the at least one matching actions, generating a candidate sponsored story based on the matching action using the matched sponsored story specification; determining privacy preferences for the subject user; and providing for display to a viewing user at least one of the candidate sponsored stories subject at least in part to the privacy preferences.
1. A method comprising: monitoring an activity stream that comprises a plurality of actions of different action types performed by users of a social networking system; storing a plurality of sponsored story specifications that each designates at least one action type to be included in a sponsored story; identifying, in the monitored activity stream, at least one action performed by a subject user, the at least one action matching an action type specified in one or more of the plurality of stored sponsored story specifications; for each of the at least one matching actions, generating a candidate sponsored story based on the matching action using the matched sponsored story specification; determining privacy preferences for the subject user; and providing for display to a viewing user at least one of the candidate sponsored stories subject at least in part to the privacy preferences. 2. The method of claim 1 , further comprising: determining a ranking of the candidate sponsored stories for the viewing user; and selecting at least one of the candidate sponsored stories based on the ranking.