1. A method comprising: determining a click probability for a first user of a social network using at least one processor, the click probability indicating a likelihood of the first user to select a first advertisement if the first advertisement is provided to the first user via the social network; determining a plurality of subscription probabilities for a plurality of respective users of the social network, the plurality of users including the first user and second users that are included in an affinity set of the first user, each subscription probability indicating a likelihood of a respective user of the plurality of users to subscribe to a paid service with respect to the social network; and determining a social network value for the first user based on the plurality of subscription probabilities; and determining whether to provide the first advertisement to the first user based on the click probability and the social network value.