For those interested in early online systems, I strongly recommend John S. Quarterman's
The Matrix: Computer Networks and Conferencing Systems Worldwide:
https://archive.org/details/matrixcomputerne0000quar/mode/2u...
I lifted a copy off a friend who was thinning his book herd a decade or so back. The first edition, published in 1990, predates the commercial Internet, World Wide Web, Linux, and all of what's transpired since, though the introduction pressages much by noting the role of existing networks in the the then-fresh events of April 15 – June 4, 1989, known as the six-four incident, and culminating in the Tiananmen Square Massacre.
The book has a 15 page section describing Usenet, including user and traffic statistics from 1979--1988, mostly compiled by Gene Spafford and Brian Reid. Usenet is only one of numerous conferencing systems covered, others being BITNET, UUCP, FidoNET, VNET, and EASYnet
For April, 1988: 381 newsgroups, 57,979 messages, 130.949 MB, 4,152--7,810 hosts (depending on who counted and how), and an estimated 141,000 readers (people) from a total online population of 880,000.
Larry Wall, working at JPL, is named ... as the author of rn.
Much of the book, though, simply discusses the many many individual computer networks. The notion of a single global end-to-end interconnected inter-network was still very much a novelty.
In one section, the fact that the principle public interconnect between North America and Europe was a single 9600 Baud link is mentioned....
