This works on platforms like HN, Less Wrong or niche subreddits, which
i) work on the reddit model (submissions + tree of comments on them) ii) are heavily moderated (e.g. no memes but also specific restrictions like on a book series subreddit to not discuss the movie adaptations)
Then this vote-based ranking makes cream rise to the top, I agree.
In general, your "depending on how best is defined in the given context" does a lot of heavy lifting.
Right, hn is 50% collaborative filtering and 50% dang
HN and other social media sites are closer to 99% free labor, 1% paid labor, like dang. Free labor writing comments, blog posts, voting/moderating, posting videos and so on. Imagine if HN or Youtube had to pay people to generate all that content[1].
I think the only pay most get, is that you get to enjoy the site content. But in the case of Youtube, they slap so many ads in front of it that you often end up paying for this free labor content just to get rid of the ads. HN doesn't do Ad walls, but is more of a sales funnel for YCombinator and harvesting whatever value they can from the data, so not so intrusive.
[1] Youtube does pay some of the more popular content creators