it started as a board for SV VC funding candidates like... 12 years ago or something with ycombinator. it's since expanded. it's a hell-hole but if you want to know what SV dorks are selling each other, it's very useful. I pay attention to it for work reasons but also because it's a weather vane for that segment of liberal opinion.
I've noticed a couple of Marxists around but that crowd is VERY lib, even the FSF group. their critiques of capitalism almost always fail to notice that capitalism is actually the problem and they frequently throw their hands up like nothing can be done at that. it's very funny when you consider how they see themselves.
Hacker news is popular among "tech people", such as programmers, web developers, system administrators, and CS academics. This follows from YCombinator mostly focusing on software startups like Dropbox, Gitlab, and Pagerduty. HN isn't really like 4chan because its well moderated, not all accounts are anonymous, and content related to YC people or companies gets automatically promoted.
Politically, HN is all over the place, but almost universally bad. Almost all of the board is made up of men who make a lot of money with computers. I wouldn't call most of the /r/neoliberal types, there are many libertarians and other sorts. It's full of gems because most of the users are sociopathic, nerds, and very liberal.
every time I see the MBTI, I get one step closer to total jokerfication