The exponential growth of Facebook during the last year, was followed by a vital public discourse and often an alert with regard to the impacts of this popular SNS on communicational and behavioural attitudes and users’ rights. In this Paper we focus on privacy issues relating to Facebook. We attempt to define the “phenomenon Facebook” as a social and communicational ecosystem in the context of Web 2.0. In this perspective we discuss the trust relationships evolved in the Facebook communities to the extent that they affect the perceptions and expectations of privacy. We refer to the privacy issues, focusing on shortcomings of the Facebook privacy policy and practices, on regulatory responses and the problems relating to consent and contract as privacy gatekeepers in SNSs. Finally, we try to identify how SNSs and Facebook pose new challenges to privacy and data protection law.