Current mobile social network Apps have never been good at helping us informed with friends’s locations, updates and posts, but far away from helping people gather together with context/location/proximity awareness. We leverage wearable technology, location/proximity sensing, and cloud system to design a hybrid cyber-physical mobile social network with missions, and solve technique challenges in the application of crowd sensing and social collaboration. The group members not only include online “friends” but also entities with whom a person has a relationship (e.g., children, elders, pets) and that have a registered wearable tag; they can interact with each other in a transparent, reactive, and proactive manner beyond the conventional online social networks (where users perform common interactions such as manually typing, searching and posting).We design a hybrid cyber-physical mobile social network ToGathor for social and crowd missions with the following salient features: crowd sensing/sourcing, crowd localizing, cooperative localization, connecting friends socially and physically, dynamic location-based checkin points, tracking nearby friends or team members or children/elders, and mission-oriented groups. ToGathor providing messaging services using hybrid connection (remote and local) and enable social applications via daily physical interaction. We bootstrap ToGathor for high scalability via back-end Cloud server with processing off-load, high throughput messaging, big data stream processing, key-value and persistent data-store.