Efficient dissemination in decentralized social networks

Online social networks (OSN) have attracted millions of users worldwide. This enormous success is not without problems; the centralized architectures of OSNs, storing the users´ personal data, provides ample opportunity for privacy violation - a fact that has raised the demand for open, decentralized alternatives. We tackle the research question: is it possible to build a decentralized OSN over a social overlay, i.e., an overlay network whose links among nodes mirror the social network relationships among the nodes´ owners? This paper provides a stepping stone to the answer, by focusing on the key OSN functionality of disseminating profile updates. Our approach relies on gossip protocols. We show that mainstream gossip protocols are inefficient, due to the properties that characterize social networks. We then leverage these very same properties towards our goal, by appropriately modifying gossip forwarding rules. Our evaluation, performed in simulation over a crawled real-world social network, shows that our protocols provide acceptable latency, foster load balancing across nodes, and tolerate churn.