They weren’t, mostly, web servers, but handled various proprietary network formats from the proprietary clients and amongst themselves. Point to point mesh connect for AIM, hub and spoke for AOL, smart clients that could route to the appropriate endpoint based on the message contents. AIM had a “reconnect here” host to client message so you could dynamically move load around for maintenance. It was a type of select or pool loop like libuv, but before we had more than a few hundred hosts to interconnect. He entire internet and all client traffic came thru one file descriptor for the dedicated Ethernet for that process. It was all straight C, timers, Various layers of network protocols (tcp, ssl, flap, etc. the AOL client servers had lots of international localizations, which could be reloaded via a TCL command. You could see histograms of al the network latencies, at various levels, in a TCL command. I think at some point we added times to the prefix of allocated memory and had histograms on memory lifetimes. (Mostly we only allocated large chunks of memory, then at steady state would shuffle stuff of of a free list.

There were a few HTTP servers written for things like AOLTV and as an RPC gateway from third parties into the “host complex” e.g. one called ewoks was used for user registration. It was headless, only gave out 302 replies or 4xx replies.