Social capital

The core intuition guiding social capital re-search is that the goodwill that others have to-ward us is a valuable resource. By 'goodwill' we refer to the sympathy, trust, and forgiveness offered us by friends and acquaintances… If goodwill is the substance of social capital, its effects flow from the information, influence, and solidarity such goodwill makes available. … these benefits are accompanied by costs and risks.

Definition
Social capital is the goodwill available to individuals or groups. Its source lies in the structure and content of the actor's social relations. Its effects flow from the 'information, influence, and solidarity it makes available to the actor'.

Social structure
…we can differentiate social capital from other types of resources by the specific dimension of social structure underlying it; social capital is the resource available to actors as a function of their location in the structure of their social relations. But what are 'social relations'? We can distinguish conceptually among three dimensions of social structure, each rooted in different types of relations:
 * 1) market relations, in which products and services are exchanged for money or bartered,
 * 2) hierarchical relations, in which obedience to authority is exchanged for material and spiritual security, and
 * 3) social relations, in which favors and gifts are exchanged. It is this third type of relationship that constitutes the dimension of social structure underlying social capital.

Relationship with other forms of capital
Social capital resembles some kinds of capital and differs from others. First, like all other forms of capital, social capital is a long-lived asset into which other resources can be invested, with the expectation of a future (albeit uncertain) flow of benefits. Through investment in building their network of external relations, both individual and collective actors can augment their social capital and thereby gain benefits in the form of superior access to information, power, and solidarity; and by investing in the development of their internal relations, collective actors can strengthen their collective identity and augment their capacity for collective action. …And, like physical capital and human capital, but unlike financial capital, social capital needs maintenance. Social bonds have to be periodically renewed and reconfirmed or else they lose efficacy. Like human capital and some forms of public goods, such as knowledge, it normally grows and develops with use-for example, trust (which we argue is a key source of social capital).

… like clean air and safe streets, but unlike many other forms of capital, some forms of social capital are 'collective goods' in that they are not the private property of those who benefit from them. This characteristic makes social capital vulnerable to free-rider problems and the resulting 'tragedy of the commons' risks.

Benefits of social capital
Direct benefits of social capital :
 * Information
 * Influence, control and power
 * Solidarity
 * Collective actors can strengthen their collective identity and augment their capacity for collective action
 * Trustworthiness of the social environment

Social capital in larger social aggregates has deep historical roots and, thus, should be treated as an exogenously given 'endowment', it is also, at least under some circumstances, 'constructible' through deliberate actions.