It's not so much the "JOBS" function that is interesting, but the
DISTRIBUTE.  JOBS packages up units of LISTSERV work in a method that
allows for the hundreds (?) of LISTSERV host machines to work on a
task.  In this particular case, it would be a DISTRIBUTE [MAIL] function
which is used to distribute ... mail to a bunch of folks.  The LISTSERV
DISTRIBUTE function often makes use of the LISTSERV distributed peer
backbone to accomplish this work.  This architecture was built upon the
Bitnet paradigm where it was cheaper / quicker to distribute a few jobs
across an NJE/RSCS network so the the resultant mail was sent from a host
closer to the intended recipient minimizing backbone bandwidth which was
much more limited and slower in the 70's thru late '80s.  Typically this
was done by "batching" multiple recipients in a single transmission
from the distributed sending host to the receiving customer mail host.

A somewhat underutilized function was for a user to build their own
Distribute Mail job to send a one-time mailing instead of creating a
genuine LISTSERV list.  Today, obviously, that function IS controlled due
to the proliferation of spammers and their tendency to abuse mail
transmission functions.

Various "routing" (through the LISTSERV hosts and RSCS links) was made by
multiple layers of software packages i.e., LISTSERV, MAILER, and RSCS itself.

Today that has been somewhat replaced by removing MAILER and RSCS
components and replacing them via DNS MX Resource Records, other
third-party forwarding agents, spam and A/V filters, and sun-spots.

/Pete