Mining Social Capital on Online Social Networks with Strong and Weak Ties

The concept of social capital refers to the advantage that is created from the structures of an actor's social ties within a network. This paper presents an approach to investigate the extent to which a particular network is characterized by brokerage or closure social capital based on triadic analysis. We split each network into two, respectively comprising of strong and weak ties. To facilitate this splitting, we measure the strength of the tie among a pair actors based on the reciprocity of their relationship and the number of their shared or mutual friends. We hypothesize that the network composed of strong ties is expected to be rich in closure triads, whereas the network composed of weak ties is expected to be rich in brokerage triads. We test our hypotheses on four popular online social networks (OSNs), namely, Facebook, Twitter, Slashdot and YouTube. Empirical analysis reports that most networks composed of strong ties comprise both brokerage and closure triads, leading to the rejection of the first hypothesis. On the other hand, all networks composed of weak ties except for Slashdot comprise a significant number of only brokerage triads, leading to the acceptance of the second hypothesis. We discuss how the motives and mechanisms of interaction on each OSN contribute to its structure in the form of strong and weak ties, which results in the presence or absence of a particular form of social capital.