I had a 486 server once. It was Novell NetWare 3.x running a LAN for a small nonprofit. Word Perfect, email, listserv, accounting and web access. Pretty sure I would never have exposed it to HN though (had it existed)...
Novell was actually quite efficient and responsive. Everything ran in ring 0, right next to the hardware. Which is also why you never applied any patch other than one from Novell...
I remember seeing a website years ago that supposedly ran on Minix on a 286. Someone had fired that up because... well, because.
I don't think it was fast, nor did it probably serve any purpose apart from existing and possibly serving some information about the software it was running.
