13. The system of claim 10 , wherein the operations further comprise storing a mapping of social activity types to weights, each social activity type having a corresponding weight.
13. The system of claim 10 , wherein the operations further comprise storing a mapping of social activity types to weights, each social activity type having a corresponding weight. 14. The system of claim 13 , wherein the social activity types comprise at least one of a like of content, a share of content, a follow of content, a comment on content, a status update, and a calendar event.