Features of online social networks are being introduced in various applications and environments, including tools supporting virtual teams and online collaboration in general. In fact, social networking has a large potential for easing collaboration, also across organizational boundaries. However, effective e-collaboration through social networks requires the development of open and interoperable systems, allowing people belonging to different organizations to create ties, reflecting real connections existing in daily activities. Attention has to be paid to identity management, for allowing users to develop their reputation consistently, and to privacy and confidentiality, for creating a more trustful environment and protecting freedom of expression. In this article, the authors propose a novel peer-to-peer system, named Blogracy, leveraging the large BitTorrent network. Its main distinguishing features are: (i) protection of users' identity and privacy, (ii) absence of central control over published content; (iii) interoperability with other systems; and (iv) low costs and scalability of the infrastructure.