Abstract: Participants in social network sites create self-descriptive profiles that include their links to other members, creating a visible network of connections – the ostensible purpose of these sites is to use this network to make friends, dates, and business connections. In this paper we explore the social implications of the public display of one’s social network. Why do people display their social connections in everyday life, and why do they do so in these networking sites? What do people learn about another’s identity through the signal of network display? How does this display facilitate connections, and how does it change the costs and benefits of making and brokering such connections compared to traditional means? The paper includes several design recommendations for future networking sites.