Elon Musk is creating a media credibility rating site to fight fake news
twitter.com
twitter.com
It only seems impossible because it's never been done, just like rockets self-landing on autonomous ocean drones seemed impossible five years ago.
When people hear "crowdsourcing" they think "free-for-all". But it doesn't have to be that way. With clear rules and strong moderation, it's possible to build a meritocracy of truth.
I would start by logging the predictions of pundits and publishing their win/loss ratios.
Next I'd index news stories published 3+ years ago where hindsight gives us greater certainty what actually happened. That would establish the Bayesian prior of credibility for each organization and author.
You'll always have trolls and propagandists with "evidence" that the world is flat but that's what shadow banning is for.
[0] https://twitter.com/NateSilver538/status/999400424435314690
[1] https://twitter.com/JamesOKeefeIII/status/999370127421378561