In Social Capital, by Nan Lin, presents some differing perspectives on social capital. I have made some notes of his assessment below, and have added some additional comments.
Bordieu - Social capital consists of social obligations or connections. It can be reduced to economic capital as it is viewed as collective asset that endows members with credits. The collective asset can be obtained through group membership.
Burt - Social capital is based on the number of people that an individual is connected to, the strength of these relationships, and the location the individual reside within this structure (see Flap's perspective). Individuals that bridge non-redundant groups of people have more social capital. Social capital accrues through bridging structural holes.
Coleman - Social capital is an aspect of social structure, and it facilitates certain actions of individuals within the structure. Social capital accrues through bonding.
Flap - Social capital consists of (1) the number of persons within one's social network who "are prepared or obliged to help you when called upon to do so," (2) the strength of the relationship indicating readiness to help, and (3) the resources of these persons.
Lin - Resources are divided into two types: personal and social. Personal resources include material objects (e.g, an airplane) and symbolic objects (e.g., a diplomas and degrees). Social resources, on the other hand, are resources accessed through an individual's social connections. Social resources, in both quantity and quality, far outweigh personal resources.
Putnam - Group level theory which tends to measure social capital collectively.
These notes are in no way conclusive or complete. However, they serve as a quick reminder to the various views.