As for CSnet, it didn't exist when Usenet started
(I don't know which was thought up first however).
Also, CSnet was not bulletin-board oriented.
I am not sure if CSnet had mailing lists anything like ARPAnet.
The big deal with Usenet/Arpanet was that Arpanet mailing lists
were poured into Usenet. At first it was a one way.
It had a big effect on Usenet volume, if nothing else!
(My history of this is weak, perhaps Bruce Jones archives have good stuff.)
Technically, Usenet probably has more in common with FidoNet.
This page last updated on: Jul 1 09:16