Nothing will give you definitive answers: email is decentralized but computer-litterate and privacy-aware people use gmail and regularly send important emails t

Nothing will give you definitive answers: email is decentralized but computer-litterate and privacy-aware people use gmail and regularly send important emails to gmail users... I agree with you that there should be some way to "quite easily" encrypt everything so that your recipient decrypts it only on its client software, though I doubt the situation will differ from the current one with emails. But "Freedom" lies in the effective ability to use it. Once all protocols are open your issue is more social than technical: for this see Elben Moglen's ideas on personal servers (tiny pluggable servers…) (even if we already have DSL boxes and even phones for small-bandwith data).