Most research regarding online social networks such as Facebook, MySpace, Linked-In and Friendster has looked at these networks in terms of activity within the online network, such as profile management and friending behavior. In this paper we are instead focusing on offline socializing structures around an online social network (exemplified by Facebook) and how this can facilitate in-person social life for students. Because students lead nomadic lives, they find Facebook a particularly useful tool for initiating and managing social gatherings, and as they adopt mobile technologies that can access online social networks, their ad-hoc social life is further enabled. We conclude that online social networks are a powerful tool for encouraging peripheral friendships, important in particular to students. We emphasize that the use of online social networks must be viewed from a perspective of use that involves both mobile and stationary platforms and that it is important to relate online and offline social practices.