6. A system to rank users in an online social network, comprising: a connectedness monitor to determine a connectedness for a user of an online social network based on a number of direct contacts and a number of indirect contacts, the connectedness monitor to assign a first weight to at least a portion of the direct contacts who have restricted respective connections with the user and assign a second weight to the direct contacts who have not restricted respective connections with the user; an interactivity monitor to determine an interactivity for the user based on a number of first interactions directed by the user to one or more second users and a number of second interactions directed at the user by one or more of the second users, generate at least one of a matrix or a vector in response to identifying an initial interaction, store the interaction count in the matrix or the vector, and update the at least one of the matrix or the vector in response to identifying a response interaction to an initial interaction; a user ranker to determine a rank for the user based on the connectedness and the interactivity; and a logic circuit to implement at least one of the connectedness monitor, the interactivity monitor, or the user ranker.
6. A system to rank users in an online social network, comprising: a connectedness monitor to determine a connectedness for a user of an online social network based on a number of direct contacts and a number of indirect contacts, the connectedness monitor to assign a first weight to at least a portion of the direct contacts who have restricted respective connections with the user and assign a second weight to the direct contacts who have not restricted respective connections with the user; an interactivity monitor to determine an interactivity for the user based on a number of first interactions directed by the user to one or more second users and a number of second interactions directed at the user by one or more of the second users, generate at least one of a matrix or a vector in response to identifying an initial interaction, store the interaction count in the matrix or the vector, and update the at least one of the matrix or the vector in response to identifying a response interaction to an initial interaction; a user ranker to determine a rank for the user based on the connectedness and the interactivity; and a logic circuit to implement at least one of the connectedness monitor, the interactivity monitor, or the user ranker. 9. A system as defined in claim 6 , wherein the direct contacts are first-degree contacts and the indirect contacts are second-degree contacts.