I really really want someone to build an open source decentralised peer to peer piece of software that does this. Something similar to bitcoin in that it's not controlled by any one person or system and anyone can join in. There are a lot of hurdles but I think it could be done and that's something I'd definitely put money towards.
For all the trashing e-mail gets on HN, it is a successful, and ubiquitous, decentralized peer to peer communications medium. It seems like that kind of thing stands little chance of taking off today where single-entity walled gardens are the norm.
