Social capital is an aggregate of interpersonal networks. Belonging to a network helps a person to coordinate his strategies with others. Where the state or the market is dysfunctional, communities enable people to survive, even if they do not enable them to live well. But communities often involve hierarchical social structures; and the theory of repeated games cautions us that communitarian relationships can involve allocations where some of the parties are worse off than they would have been if they had not been locked into the relationships. Even if no overt coercion is visible, such relationships could be exploitative.