"This is one of those ideas that's like an irresistible force meeting an immovable object. On one hand, entrenched protocols are impossible to replace. On the other, it seems unlikely that people in 100 years will still be living in the same email hell we do now. And if email is going to get replaced eventually, why not now?" - Paul Graham, Frighteningly Ambitious Startup Ideas
Maybe email isn't as immovable as we all seem to think it is.
The worrying thing however is that so many of the touted replacements are proprietary systems like Twitter, Facebook or Google+.
For all their problems, www and smtp are standards - you can use them with a whole range of different browsers/clients, from kludgy bash scripts to the fanciest commercial GUI offering - and they just work. (Well 99.9% of the time).
There was a time when IBM SNA, DECnet, CompuServe battled it out - and all lost to the OPEN, and Free (both ways) Internet and it's protocols.
Maybe email isn't as immovable as we all seem to think it is.