Social characteristics of mobile users have been extensively used to streamline networking services and applications in delay-tolerant networks (DTNs). In this chapter, we explore the application of social network analysis techniques in DTNs with a focus on social characteristics and human mobility models, as well as social-aware data routing and forwarding protocols. First, common concepts and metrics to measure social properties of mobile users are explored. Then, pioneering social-based mobility models, which are utilized to evaluate social-based protocols in DTNs, are elaborated. Finally, social-aware data routing and forwarding algorithms with respect to community structure, multicasting, user selfishness and incentive schemes are presented.