Online relationship formation through social networking sites helps to meet the developmental need for intimacy in emerging adults. Through the use of the "rich get richer" and the "social compensation" hypotheses, it is evident that personality characteristics such as extraversion and introversion impact online relationship formation. However, there is a lack of research on the amount of relational benefits, in terms of social capital, accrued from these relationships. This study addressed this issue by examining how the online communication styles of extraverts and introverts mediate the relationship between the personality variables and the accumulation of online social capital. Support for the rich get richer hypothesis was found, with extraversion leading to the accumulation of bonding social capital. This relationship was mediated by the active communication behaviors of extraverts.