Offering a viable alternative architecture to centrally-controlled global digital platforms for social networking is an open challenge. Here we present a grassroots architecture for serverless, permissionless, peer-to-peer social networks termed grassroots social networking. The architecture is geared for roaming (address-changing) agents communicating over an unreliable network, e.g., smartphones communicating via UDP. The architecture incorporates (i) a decentralized social graph, where each member controls, maintains and stores only their local neighbourhood in the graph; (ii) member-created feeds, with authors and followers; and (iii) a novel grassroots dissemination protocol, in which communication occurs only along the edges of the social graph. The architecture realizes these components using the blocklace data structure -- a distributed partially-ordered counterpart of the replicated totally-ordered blockchain. We provide two example grassroots social networking protocols -- Twitter/LinkedIn-like and WhatsApp-like -- and address their safety, liveness, privacy, and spam/deep-fake resistance, demonstrating how centrally-controlled social networks could be supplanted by a grassroots architecture.

翻译：为中央控制的全球数字社交平台提供可行的替代架构仍是一个开放挑战。本文提出一种面向无服务器、免许可、点对点社交网络的草根架构，称为草根社交网络。该架构专为在不稳定网络（例如通过UDP通信的智能手机）上漫游的地址变更代理设计，包含：（i）去中心化社交图谱——每位成员仅控制、维护和存储图谱中的局部邻域；（ii）成员创建的动态信息流（feeds），包含作者与关注者；（iii）一种新颖的草根传播协议，仅沿社交图谱的边进行通信。该架构利用区块花数据结构（blocklace）实现上述组件——这是一种分布式偏序结构，与复制全序区块链相对应。我们提供了两个草根社交网络协议示例——类似推特/领英和类似WhatsApp——并讨论了其安全性、活性、隐私性及抗垃圾信息/深度伪造能力，展示了中央控制社交网络可如何被草根架构替代。