This was the problem with google wave. It tried to solve the distribution problem, but that's easy and solved. The real problem is the opposite, signal-to-noise and information overload.
Also, there is the general problem of keeping information up to date. If every new participant to a conversation has to follow all the convolutions of the original email thread (some of which may be missing because face-to-face meetings probably happened at one point) then that's a huge waste. Figure out how to create a system which naturally encourages people to sum up the current state of the discussion (perhaps with automated aids) and you'll be ahead of the game.
I feel like google wave tried to tackle these problems as well.
Specifically, it was possible for people to join and leave a conversation much in the same way that facebook messaging threads work now.
While Wave did subscribe fairly heavily to the traditional message and reply model it also had support for wiki-style messages, so it was possible for a summary to be maintained in the top message of each thread. (The instant replay tool I always thought was very cool, too.)
And towards the end it did start to introduce some tools to encourage people to summarise information (although admittedly nothing revolutionary). I'm mainly thinking of its widgets for event organisation, date planning and voting which are always horrible to do via email.
I think Wave had a lot of problems and, it may be, that the problems it did solve it didn't solve well but I do think it at least tried and had a few good ideas.
Also, there is the general problem of keeping information up to date. If every new participant to a conversation has to follow all the convolutions of the original email thread (some of which may be missing because face-to-face meetings probably happened at one point) then that's a huge waste. Figure out how to create a system which naturally encourages people to sum up the current state of the discussion (perhaps with automated aids) and you'll be ahead of the game.