This chapter considers the mechanisms by which social network site (SNS) use is associated with social capital processes, such as supporting beneficial interactions, information exchanges, and relationship maintenance. In doing so, we consider both the high-level affordances of SNSs, such as the persistence and visibility of content, as well as specific features of these sites, such as the profile. The chapter will proceed as follows: First, it will provide a review of research on social media and social network sites, highlighting the primary features and affordances of these sites. It will then synthesize the social capital literature, which is helpful for understanding how we access important human resources such as social and informational support from our social connections, before linking the two streams of research on SNSs and social capital by highlighting some of the key findings in recent years. In the next section, we turn to Ellison and boyd's (2013) revised definition of SNSs to consider the role played by the profile, the articulated network, and the broadcasted stream of content in social capital formation and development. To conclude the chapter, we draw from multiple research streams to examine social grooming practices in SNSs, focusing on the role of visible micro-transactions such as "liking" a comment on Facebook.