[rayiner]

http://en.wikipedia.org/wiki/Bulletin_board_system ("A bulletin board system, or BBS, is a computer server running custom software that allows users to connect to the system using a terminal program. Once logged in, the user can perform functions such as uploading and downloading software and data, reading news and bulletins, and exchanging messages with other users through email, public message boards, and sometimes via direct chatting.")

HN is actually a fairly primitive BBS running over TCP/IP.

[amyjess]

I'd argue that the BBS is the earliest form of social media (or one of the earliest, at least).

[Torgo]

Finger?

https://en.wikipedia.org/wiki/Finger_protocol

[raverbashing]

I know what a BBS is, I used them

(I'd say HN is not one, since we don't use a terminal program to access it and not using a modem over POTS)