I don't like the mob thing either but it's how large group dynamics on the internet work (by default). We try to mitigate it where we can but there's not a lot of knowledge about how to do that.
1. Remove non-hacker type content (i.e. news concerning the death of the Queen and anything Trump). Or move it to an off-topic list that doesn’t appear on the front page or other lists. It’s not in the spirit of the site, and I come to this site to avoid it. I treasure the actual hacker discussions on this site and feel like those articles do not add to or even diminish the value. Plus many of those stories that make it to the front page tend to be very focused on America / the English-speaking world.
2. Remove karma or deemphasize it. Discussion is important. Arbitrary numbers are not and (unintentionally) influence how people engage.
3. Add a higher barrier of entry. It’s great how you have to earn 501 karma before you can downvote. Perhaps up that limit and/or require a year old account. Prevent new accounts from posting for a period such as 3 months. This would allow people to pick up on the culture and etiquette before they begin commenting; like an apprentice studying under a master before beginning his own work. I’d even consider adding a simple quiz to create an account. Something that proves you’re a hacker in spirit. The purpose of all this is to prevent the website from stooping to Reddit standards and keeping the quality of content high. Those who engage in discourse on this site should be here because they really want to be part of the community and are willing to jump through a few hoops.
4. Create smaller communities. Find a way to group people across time zones into smaller pockets. A classic issue on Reddit is that smaller subreddits for niche hobbies are often great until they reach critical mass. Past a certain number of users, the culture is lost and everything appeals to the lowest common denominator. If hn is to grow too large, perhaps there could be a way to artificially divide it up.
5. Increase the damn font size!
Thanks for all that you do :)