Usually: voted on/curated by members who are specialized in some way (reddit, so, hn, wikipedia to a degree).
The fallbacks are editorial sites.
If you make a search engine that focused on indexing user-curated sites + results outside of that that are themselves curated/voted-on by your search engine users (ie, you and others could upvote axios and Amazon as a good source), I think you'd have an interesting model. Basically, take the HN/reddit model to search itself.