[spinningslate]

>Stack Exchange which is way more rich and runs on small (relative) infra.

Yes, I've heard that SO runs on relatively simple and modest infra. And agree that would be a good example.

>HN is not user friendly

How so? I find the HN UX a refreshingly simple and effective experience. It might not have all the bells and whistles of newer discussions fora, but it doesn't obviously need them. I'd say it's a good example of form/function well suited to need. Not perfect perhaps, but very effective.

YMMV of course.