5. The method of claim 1 wherein the social quality score includes: a probability of a social engagement by a user in response to the content item being published; and a social value of the social engagement, wherein the social value indicates expected interactions by the user in the social network that result from the published content item; and determining the social quality score for each content item is based, at least in part, on a product of the probability of the social engagement and the social value of the social engagement.
5. The method of claim 1 wherein the social quality score includes: a probability of a social engagement by a user in response to the content item being published; and a social value of the social engagement, wherein the social value indicates expected interactions by the user in the social network that result from the published content item; and determining the social quality score for each content item is based, at least in part, on a product of the probability of the social engagement and the social value of the social engagement. 11. The method of claim 5 wherein the social value of the social engagement is based on a point system that assigns different points for different types of social engagements.