I am old enough to remember Usenet. All you needed was an Internet connection, a usenet client, and access to a usenet server.
Most ISPs provided usenet access just like they provided an e-mail address at the time. So it was no more difficult to be involved in usenet than it was to have e-mail.
In modern terms, usenet would be reddit if it was distributed (so anyone willing to set-up their own server could run a node and let people connect to it). But for end-users it was as simple as having an e-mail account and a client application on your computer.