Requirement:
An existing friend-to-friend P2P ‘backbone’.

Idea
– Push-notifications of meta-data belonging to a specific ‘topic’
– Each peer acts as a router. Peers subscribe to listen to a ‘topic’ if they, or one of their peers wants to subscribe to a topic. Same as how multicast works now.

Some details
– topics are subscribed to by their ‘hash’, so it’s not obvious to casual observers/intermediaries what the topics are.
– topic metadata is sent encrypted (again so casual observers have no idea what is being sent).
– since you get the metadata directly from your friend – you have no idea who the originator of the topic data is (it may even be him, it may not be).
– only metadata is sent. It should be small with links to the full content to retrieve from P2P network in the usual way.
– the idea is somewhat similar to usenet, but without each node storing a copy of the entire set of data.
– metadata and data formats should be structured to encourage ‘machine friendly’ topics, i.e. stock prices, forex data, weather, etc.