Kawachi et al. [21] define social capital as “ consists of features of social organization—such as trust between citizens, norms of reciprocity, and group membership—that facilitate collective action”. Social disconnectedness can be measured through size of social network,level of in frequent participation in social activities and perceived isolation through aspects of loneliness and perceived lack of social support [5]. Social capital,in main part includes: social inclusion,social participation and social support [53]. Social inclusion implies access—for example, older people may have less physical access to social groups. Social participation describes how much a person engages with a community. And, social support implies how much support one can get from the community. This support and interaction, traditionally, has been derived from physical social networks—family, churches, hobby groups. We have, on the other hand, increased online connectivity evidenced by the unprecedented growth of many social networking sites. What, if any, is the relation between aspects of mental health, say mood, and “online social capital”? At a more fundamental level, can we measure it through social media? This paper examines these questions.