Providing content items based on user affinity in a social network environment

A computer program product embodied on a non-transitory computer readable storage medium including instructions, which when executed, cause a processor to:

• receive a plurality of candidate content items for a viewing user, each content item associated with an action performed in a social networking system and each content item identifying a respective user who is connected to the viewing user in the social networking system;
• define, for the viewing user, a first plurality of weights for a corresponding plurality of action classes, a weight for an action class indicative of a significance to the viewing user of information about actions of that action class;
• determine, by the process, an affinity of the viewing user for each of the plurality of candidate content items, by:
• identifying a respective action associated with the content item,
• determining a first numeric rating for the respective action associated with the content item based on a respective relevance to the viewing user of the respective action,
• determining an action class of the plurality of action classes for the respective action, and a corresponding first weight, from among the first plurality of weights, associated with the determined action class, and
• computing the affinity for the content item based on a first weighted measure of the first numeric rating for the respective action and the first weight associated with the determined action class, the weighted measure obtained by scaling the first numeric rating by the determined first weight;
• compare the viewing user's determined affinities across the candidate content items;
• and
• select, for display to the viewing user, one or more of the candidate content items based on the comparison.