In ARPANET days, many systems across the Net permitted access either without logging in, or permitted you to easily create an account. The dialup TIPs (Terminal Interface Processors) long had no authentication requirements, and the effort to implement those (TACACS as I recall) never really functioned well. This all was fairly practical so long as relatively few people had the hardware and knowledge to use these systems. I had a map of the ARPANET taped to my bedroom door and for a long time I knew the host numbers for every site (I was on ARPANET site #1 at UCLA, which was especially easy to remember). I still can recall many of those host numbers. Those are neurons I'm never getting back.