Despite their tremendous success, centrally controlled cloud based solutions for social media networking have inherent issues related to privacy and user control. Alternatively, a decentralized approach can be used, but ensuring content availability will be the major challenge. In this work, we propose a time based user grouping and content replication protocol that exploits the cyclic diurnal pattern in user uptime behaviour to ensure content persistence with minimal replication overhead. We also introduce the concept of β-availability, and propose a mechanism for ensuring the availability of at least β members within a replication group at any given time. Simulation results show that a 2-availability grouping policy delivers high content
persistence without incurring significant network and storage overheads.