Towards a Three-tiered Social Graph in Decentralized Online Social Networks

We developed an approach and a software architecture for decentralized social networking services, focusing on the central role of the smartphone. We presented this work as a paper at the HotPOST 2015 workshop (co-located with ACM MobiHoc 2015) and received the Best Paper Runner-Up award! You can find the full paper here (PDF).

Online Social Networks have become one of the main tools for interpersonal online communication. In the age of the smartphone, mobile user scenarios become more and more important for Online Social Networks. Smartphones enable location-based and context-aware services, but bring the increased risk of privacy violations – at least in centralized OSN architectures. Decentralized Online Social Network architectures are promising as they inherently offer better privacy and less dependence on a single service provider, but they bring new challenges regarding core features of Online Social Networks. We introduce a three-tiered view of the social graph and propose a new architecture for decentralized Online Social Networking applications, supporting the three-tiered view and focusing on location-based and context-aware user scenarios.

The three tiers in our system, allowing users to connect with friends, users in similar contexts, and users at the same location.
The T3 architecture using two layers of directories for looking up users in the three tiers.
Best Paper Runner-Up award.