Group communication is a powerful tool that simplifies the development of dependable systems, but widespread adoption of the paradigm has been limited. The main problem is that existing systems lack important forms of scalability and clean OS embeddings that can sustain high performance. QuickSilver is a new platform designed to enable casual use of groups on a massive scale. Our approach relies on a new way of constructing hierarchical, scalable protocols. Groups are accessed via typed communication endpoints; an underlying properties framework promotes flexibility and modularity.