@art297 wrote:
@Andygray: A little more digging indicated that they were using BITNET (i.e., Because It's There NET, see: https://en.wikipedia.org/wiki/BITNET). Email, via BITNET, was available as early as 1981.
I know informal SAS discussion was active on BITNET as early as 1983 since I used it send message from CUNYVM to YALEVM.
LISTSERV didn't start until 1986 and I would not be surprised if SAS-L wasn't one of the first listserv mailing lists.