This is a good place to reference cypherpunk co-founder Tim May's email from 1992:
http://www.activism.net/cypherpunk/crypto-anarchy.html
Took the world long enough to catch up.
Took the world long enough to catch up.
Sounds like the product side has been figured out... the essay is pretty thorough.
Various issues: C used (huge flag), little progress yet, arbitration can't help in subjective/unverifiable/misleading data situations, anynomity will drag in the trash-sellers by the dozens, entirely unsourced data -even when true- is not as useful as sourced stuff (which you'd call "actionable"), de-duping information is impossible, what's the arbiters' motivation to be honest and not attempt to contact either side for bribes (or vote against "truth" for lolz), etc.
But mostly: Just think of the Signal/Noise ratio. Everyone will be trying to abuse this.
Even the dumbest, shotgun, numbers-game approach would have returns: Keep listing seemingly interesting stuff that is actually misleading/incomplete/bad/resold/... and eventually some of your transactions will not be reverted by arbitration.
And this is anonymous crowd-funding, you say?
...anonymously crowdfunding this half-thought idea with bitcoin.