Social relations yield information at minimal additional cost. [definitional]
An important form of social capital is the potential for information that inheres in social relations. Information is important in providing a basis for action. But acquisition of information is costly. At a minimum, it requires attention, which is always in scarce supply. One means by which information can be acquired is by use of social relations that are maintained for other purposes.
XREF: Connects to Burt's structural holes and Granovetter's weak ties literature on information advantage in networks.
Coleman, SocialCapitalCreation-1988, loc. 99