  Distributed online social networks (DOSNs) were first proposed to solve the
problem of privacy, security and scalability. A significant amount of research
was undertaken to offer viable DOSN solutions that were capable of competing
with the existing centralized OSN applications such as Facebook, LinkedIn and
Instagram. This research led to the emergence of the use of peer-to-peer (P2P)
networks as a possible solution, upon which several OSNs such as
LifeSocial.KOM, Safebook, PeerSoN among others were based. In this paper, we
define the basic requirements for a P2P OSN. We then revisit one of the first
P2P-based OSNs, LifeSocial.KOM, that is now called LibreSocial, which evolved
in the past years to address the challenges of running a completely
decentralized social network. Over the course of time, several essential new
technologies have been incorporated within LibreSocial for better
functionalities. We describe the architecture and each individual component of
LibreSocial and point out how LibreSocial meets the basic requirements for a
fully functional distributed OSN.
