INTRODUCTIONAn on-line community has been defined as -a collective group of entities, individuals or organizations that come together either temporarily or permanently through an electronic medium to interact in a common problem or interest space‖ (Plant, 2004, p. 54). Plant noted in 2004 that there were an estimated 400,000 communities on the World Wide Web, with over 300,000 on-line topic-based discussion boards used by such communities. Recently, however, global interest in social networking has accelerated markedly: in 2010, it was estimated that the active unique audience for social networking sites globally grew by around 30% in one year, from 244.2 million to 314.5 million (Nielsen Wire, 2010) -Grove, 2007), more recent data indicate that social networking is still on the rise (Nielsen Wire, 2010). The QQ social network in China, now arguably the largest in the world, has around 637 million active users, while Facebook has more than 517 million such users (Tencent, 2011; Miniwatts Marketing Group, 2010). Within the general category of online communities, Boyd and Ellison (2007) defined social networking sites as web-based services that allow individuals to (1) construct a public or semi-public profile within a bounded system, (2) articulate a list of other users with whom they share a connection, and (3) view and traverse their list of connections and those made by others within the system. (p. 1)