Aussies' fix for 'stagnated' email 
What I'd really like to see is a P2P, encrypted, bittorrent-based mail system, basically something that works similar to bitcoin, but used for sending encrypted mail instead.No central servers, just a single blockchain recording all encrypted messages on the network and shared over a bittorrent network, and an easy-to-use client that doesn't make normal people think too hard.Encrypt a message with your recipient's public key, submit it to the network, it's accepted into the blockchain, and they decrypt it on the other end with their private key when the msg propagates to their client.  Private (at least until computing power catches up with the encryption algorithm), decentralized email without ads, popups, etc.Give it a nice Apple-ish/fluent.io-ish/sparrow-ish interface, transparent encrypting and decrypting, and some way of optionally associating email addresses with public keys so normal users don't have deal with intimidating hashes (optional only though, still want the ability to send directly to more anonymous public keys).While you'd still need some method of preventing block chain forking, you wouldn't have to worry as much about double spending and transaction verification since you don't care whether someone sends the same message multiple times to different recipients (as you do with bitcoin).One of the biggest problems would be dealing with exponentially increasing blockchain size.  Bitcoin already has this problem and its transactions consist only of relatively terse amounts of data.  With full emails (and attachments?) you'd have to implement a method of cropping and perhaps archiving the blockchain, or otherwise solving that problem, or it will quickly become unweildy and destroy the user experience (esp for people with slow connections).Perhaps clients store the blockchain a certain number of blocks back, and then beyond that they only store their own sent and received messages?  Not sure...The genius of bitcoin is that it is a solution to a difficult algorithmic problem in distributed systems [1] which can be repurposed for other implementations.  It is already being repurposed for a distributed DNS [2] and distributed voting systems for elections [3], why not a distributed encrypted email system as well?Just throwing this out there without really thinking it through thoroughly atm...  Thoughts?  Feasible?  Probably the biggest problem is knowing that one day all your emails would essentially become public domain when hardware catches up...1.  http://en.wikipedia.org/wiki/Byzantine_fault_tolerance#Origi...2.  http://dot-bit.org/3.  ddg-fu failing me atm, will add this later.