5. The method of claim 1 , further comprising calculating a user-engagement score for each card in each card cluster based on one or more user-engagement factors, wherein the user-engagement score of each card in each card cluster is above a threshold user-engagement score.
6. The method of claim 5 , wherein one or more of the user-engagement factors comprise one or more of demographic information, current information, or social-graph information of the first user.