Privacy is widely viewed as an interpersonal boundary regulation process in the context of online social networks (OSNs). Mediated by technologies provided by the OSNs, users manage both identity information and social relationships on OSNs. While previous studies mainly focus on users’ information sharing and disclosure behaviors from an individual perspective, this work looks into the social nuances of users’ interactional privacy concerns within their social circles from an interpersonal perspective. Through a case analysis of launching “Friendship Pages” by Facebook, we aim to examine the trigger conditions under which users perceive the launch of such feature to aggregate interpersonal interactions as privacy problems. This work calls for more research in conceptualizing and measuring users’ interpersonal privacy concerns in the context of OSNs. We conclude this work with a discussion on research challenges in support of mitigating users’ interpersonal concerns in OSNs.