This is why I believe in the federated client-server model. It is much easier to build a system with a few trusted parties that a system with zero trusted part

This is why I believe in the federated client-server model. It is much easier to build a system with a few trusted parties that a system with zero trusted parties. Eg in XMPP, only your server sees your IP address until you initiate some out-of-band p2p thing such as file transfer. Federated client-server architectures such as email and XMPP are also pretty well understood by now, especially email has been around a long time. Trade-offs, trade-offs everywhere!