The idea of social capital has been around as long as groups of people have coexisted. The core principle of social capital is that all social networks have value, and norms of reciprocity exist within these social networks.
How Is Social Network Value Determined?
JFK School of Government professor Dr. Robert Putnam points out that social capital stems from a variety of sources:
- Information exchange – e.g. current events, college education, learning about political candidates, etc.
- Increased solidarity amongst networks – i.e. adopting a “we” mentality over an “I” mentality.
- Norms of reciprocity within and between social groups 
A common thread throughout the idea of social capital is the necessity of creating bonds not only amongst like-minded individuals, but also bridging networks to connect with more diverse groups of people. These ideas of in-group and generalized bonding are essential to fostering norms of reciprocity.
These norms help maintain balance within groups and increase the overall value of those networks.
What Are “Norms of Reciprocity?”
In social psychology, a norm of reciprocity is simply an expectation that people will behave in a “tit for tat” manner when given the opportunity. This can be either positive or negative. The expectation is that people will respond to beneficial behaviors with reciprocal acts, while they will respond with hostility towards any harmful or negative behaviors.
Norms of reciprocity are central to the idea of social capital because they often dictate the behavior of an entire network of people. Positive norms of reciprocity encourage groups of people to work cooperatively, while negative norms of reciprocity serve as deterrents to harmful or violent behaviors.
What Role Does Social Media Play?
Prior to the development of social platforms like Facebook, Myspace and Twitter, social capital was accrued through fostering relationships within a geographical community. Examples of this would be barn raisings and barter systems in the pioneer days, groups of women caring for the entire community’s children or even a neighborhood potluck supper.
The advent of Internet social media platforms has greatly expanded the possibilities for network creation. In fact, studies have shown that those who use the Internet regularly have much wider networks than those who use it infrequently. This makes sense, because the Internet allows people to connect with others outside their geographical areas in addition to keeping in touch with acquaintances. This allows for bridging between networks as well as strengthening existing networks.
Another benefit to Internet users is the ability to preselect for groups and individuals with similar viewpoints and interests. Prior to the Internet, this sort of preselection was only available through local organizations like churches, clubs, schools or bars. Now, Internet users can connect with anyone on a global scale.
The Internet has revolutionized the ability to generate social capital. Humanity now has the chance to create a web of interconnected social networks with virtually unlimited opportunity to accrue social capital. This social capital has the potential to lead to trust, reciprocity, information sharing and cooperation on a global scale.
 Ya-Ru Chen, Xiao-Ping Chen and Rebecca Portnoy (2009). To whom do positive norm of reciprocity apply? Effects of inequitable offer, relationship and relational-self orientation. Journal of Experimental Social Psychology