Social Networking Sites (SNS) are one of the most popular business models on the Internet at the

moment. At the same time, Social Networking is increasingly interesting as a topic of research in

Information Systems. Drawing on existing research in the field, in this paper we propose to distinguish

ISN (Internet Social Networking) as a phenomenon from its concrete manifestations in the various

SNSs in the marketplace. On the basis of this distinction we take to the classification of SNSs grounded

in real-life marketplace variety. In doing so, we identify seven different classes of SNSs. We argue that

a typology of SNSs is useful for shaping our understanding of the diverse nature of ISN as existing in

concrete manifestations. Most importantly, our classification makes accessible existing research for

conceptually sound meta-analysis research. In order to fully grasp the phenomenon of ISN we also

propose to include in the definition web sites that feature only certain aspects of ISN, while

networking is not their core feature. Using our classification we discuss future research direction