Reputation systems such as HN itself are another approach. These might not scale; or they might require an eigentrust-like system to scale; or scaling via eigentrust might create and reinforce the same kind of filter bubbles we see on social media. Who decides who’s a climate expert?
Steemit is an attempt at a blockchain-based reputation system. Whenever I’ve looked, it’s been dominated by low-quality content, mostly about crypto itself. Maybe this is growing pains, or maybe a reputation system needs a different go-to-market (that bootstraps from an existing platform or community), or maybe wedding reputation to crypto — or at least to crypto that pays out — just isn’t a good idea. (You didn’t exactly suggest that, either; I just riffed my way over to it.)
sometimes it'll be simple arithmatic, other times multi-variable calculus.
By all accounts Citizendium failed pretty spectacularly.