Can someone explain to me how PG funded Reddit when it was more like a HN clone?
Reddit was originally written in Lisp. Paul Graham had actually written an article about how Lisp was his secret weapon when building his Yahoo-acquired Viacom. Reddit was one of the first YC companies so I assume their language choice was inspired by this.
Soon after launch reddit had performance issues and was rewritten in Python. This improved the site stability but angered one of reddit's original user base of Lisp fans. Around the same time Paul Graham started hyping a new Lisp dialect he was writting called arc [1]. It's what powers HN.
Arc stores the stack and a set of continuations for each possible client action in memory on the server. These are referenced on the client by a fnid. This is actually the source of the next-page errors you'll see here; continuations are purged in least recently used fashion so as HN outgrows its single server the lack of memory makes sessions expire more quickly.
I believe both HN and reddit (which had a second Python-based rewrite) are now open source. There is nothing stopping Paul Graham from using reddit's source code; but I believe the arc code is leaner. HN runs on a single piece of hardware to this day.