It's been fun to play with truly ancient "BBS" programs
on retro systems. Things like `BBOARD` on TOPS-20 or
`forum` or `xforum` on Multics are both very usable, and
also quite interesting in their own right.
`BBOARD` was built on top of the `MM` mail program
written at Columbia University and shipped with TOPS-20;
it's quite capable, and extant versions of TWENEX ship
with some old content (the infamous "Goodbye" message
from the SAIL PDP-10, for instance).
`forum` on Multics is similarly useful; there the metaphor
for a topic is a "meeting". This was reimplemented for
Unix by the MIT Student Information Processing Board:
https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.31.8576&rep=rep1&type =pdf
One can understand why these did not become widespread
in the hobbyist community: the systems they ran on were
room-sized and cost millions of dollars. Still, as
conferencing systems they're quite useful now.
And of course, there's PLATO on emulated CDC cyber machines,
CONFER on MTS, etc.
--- Mystic BBS v1.12 A48 (Linux/64)
* Origin: Agency BBS | Dunedin, New Zealand | agency.bbs.nz (21:1/101)