See: List of Concepts and Concept: Social Capital
Affinity refers to the willingness of an individual to work towards the betterment of his community, without expecting a clear and measured reward in return. The more Affinity that the members of a Community have on average, the more likely they are to pass the Open Fridge Test (Concept: Open Fridge Test).
Peter Block touches upon the concept of Affinity in his book, Community: The structure of belonging by Peter Block, but refers to those members who have Affinity as “Citizens”.
The key characteristics of a Community member who possesses Affinity will be a willingness to embrace accountability, sacrificing time and/or effort for the Community and having his individual identity be linked with the group identity.
See also:Concept: Citizenship (as per Peter Block), Concept: Value Alignment and Concept: The Identity Stack