Telnet, SSH, and welcome banners
I've been using SSH so long that I'd forgotten about /etc/issue. It turns out SSH can send a pre-auth banner as well, though obviously not before you've sent your username. Not that there are many legitimate use cases for knowing a hostname or IP without a username. Even with a BBS you could just put "login as guest" alongside the hostname and maybe port.
I remember IBM used to have pretty elaborate banners on their login screens.
A social network for the 19A0s.