1. A system comprising: a computing device; and a computer-readable medium coupled to the computing device and having instructions stored thereon which, when executed by the computing device, cause the computing device to perform operations comprising: identifying a set of items that are displayed to a user of a social networking service, one or more items of the set of items comprising digital content distributed using the social networking service and being associated with a plurality of item features, the plurality of item features comprising item-dependent features and user-dependent features; for one or more items in the set of items, receiving a plurality of feature values, each of the feature values for each item of the one or more items being associated with one of an item-dependent feature and a user-dependent feature; receiving a plurality of probabilities, each of the probabilities of the plurality of probabilities being associated with a group of a plurality of groups and reflecting a likelihood that the user is a type of user associated with the group, each group of the plurality of groups including a set of weights, wherein each weight of each group is associated with an item feature of the one or more items; for one or more items in the set of items, determining an item score for the item based on i) for each group, a weighted feature value associated with each item feature of the item for the group and ii) the probability associated with each group, wherein the weighted feature value for each item feature for each group is based on i) the feature value of the item feature and ii) the weight associated with the item feature for the group; and determining a subset of items to be displayed to the user based on the item scores for each of the one or more items, the subset of items comprising items of the plurality of items.