This paper examines the role of voyeurism in motivating teen use of social network sites (SNS). our aim was to understand the purpose, benefits and importance of teen social monitoring activities in SNS. we found that voyeurism was commonplace, habitual and central to teens’ enjoyment of the medium. It enabled them to clarify their own identities, develop relationships, boost self-esteem and moreover was highly entertaining. SNS have blurred the boundaries between public and private; enabling socially accepted ‘mediated voyeurism’ and reconfiguring social norms around privacy, disclosure and observation of others. we argue that voyeurism is the common strand drawing all of the motivations for using SNS together.