Are there any stats how many active users does HN have, on how many servers it runs, on which database etc.?
Because I have recently wanted to look at my older saved/upvoted posts/comments on reddit and found out that you can look only at last 1000 posts and it does various other things to save resources. HN doesn't seem to do things like that and still feels much snappier than reddit (yes reddit has much more users, but still impressive imho).
It's hard to count active users because you have to define them in order to count them, and we make a point of not tracking people that much. We can count accounts and unique IPs, and that's about it. But it's basically about 5M readers a month, give or take, as far as we can tell. It grows linearly, with large swings. If you step back 10 feet from the graphs and squint, it's basically a straight line for the last 10 years. We like it that way; we wouldn't want to go full Haskell and avoid success at all costs, but we don't want hockey-stick growth either. HN is not a startup!
It runs on one server. Actually the app server (written in Arc) runs on one core. But we have some caching in front of that for logged-out users.
Of course there are assumptions involved in mapping that to userbase size or whatever, but it would still be interesting.