1. A method comprising: receiving search criteria from a first user of an online social network, the search criteria comprising one or more interests; selecting, using the one or more computer processors, one or more second users of the online social network who meet the search criteria, the selecting of each second user being based on: (1) the one or more interests of the search criteria, and (2) the interests of the second user, estimating a probability of compatibility of each pair of interests, each pair including a first interest from the interests of the first user and a second interest from the interests of the second user; calculating, for each second user, a total probability of compatibility score for all interests with respect to the first user; and sending information associated with the one or more second users to the first user.