It would be interesting if instead of just up and down arrows, you could tag posts as "insightful", "funny", or "inspiring". Too often, the up votes are used for things that are funny, and throwaway one liners and memes dominate all the popular subreddits. I would love to support by insightful and get discussions similar to HN.

Uhm.. I have a very low Slashdot ID number, so I saw that site develop from its start (19 years ago). Back then it was what HN is now. They have those things. It has become unreadable and unusable (has been for years now) - the most idiotic and trite one-sentence statement is tagged "insightful" if it the visiting crowds like it (which happens a lot). Go and see for yourself, if you dare: https://slashdot.org/

Example - and I clicked exactly once on a headline and selected the very first comment tagged "Insightful", so I made no attempt to find an example that fits my narrative:

  Win 10 is good OS that would be quickly adopted if/when MS
  decided to remove or make optional bolted-on telemetry
  malware. Such "feature" is simply not acceptable on a non-free 
  product.

That's it, that's the entire statement. I have to add, for those who don't know the site, only a few people have mod points at any given time (you get 5 or 15, distributed randomly after an internal algorithm giving the active users more and more often), so they are precious. Less than 10% of articles are tagged at all for an average topic, so one would expect the ones marked "Insightful" or "Interesting" to actually be just that.

If you now think "They need meta-moderation, moderation of the moderators! This should improve quality!" - well, I'm sorry to tell you they've had just that for ages...

So simply implementing any mechanism in software is not sufficient. There is no magic algorithm or method, thus far anything someone tried eventually deteriorated. I must say reddit is actually doing surprisingly well, mostly because they managed to have "sites with in the site" with their individually managed subreddits.

One problem with /. is that it favors the quick post. The maximum score is +5, so the tiebreak of whoever posted first comes into play very quickly. So there is a race to post quickly among those who want their opinion to be heard.

Can they not do exactly that with their subscriptions? Unsubscribe from AdviceAnimals and subscribe to AskHistorians.

There's a need for in-sub filtering too for non too specific subs. It's said to be possible with the Reddit Enhanced Suite thing ? but I never used it. I just echo what people say.

Sure for very narrow subs, with adequate moderation manpower, the filtering can be done this way.

But you can accomplish the same thing by creating new more moderated subs. That's why we have /r/AskHistorians in addition to /r/history. If the sub isn't specific enough the solution shouldn't be to falsly and silently fragment the sub's users via user-side filtering, it's to explicitly split off a different community that behaves the way you want. In that way there is no "non too specific sub".

If you participate in a subreddit, but filter out 70% of the content, in what way are you participating?

Sure, but things are wavey and blurry, you can't always foresee if a dedicated sub should be created, sometimes it's in waves.

True, but if your users are filtering out parts of the conversation you'll never reach a point where it's obvious there should be another community created, you'll just have multiple communities talking past each other.

Sometimes there is a mix of fluff and insightful comments in the same subreddit, or even in the same comments thread.

Which is generally what most people like. But if you only want the insightful, in-depth comments you're more likely to get them in a subreddit dedicated to those types of comments then randomly in a more general subreddit. There are even subreddits dedicated to finding those few random insightful comments out in other more general subreddits, if that's really what you're looking for.