Accessing a BBS required some level of understanding of computers and telecom gear which tended to filter out a good segment of the population. In the US local

Accessing a BBS required some level of understanding of computers and telecom gear which tended to filter out a good segment of the population. In the US local phone calls we’re unmetered but lines were expensive so most BBS’s in the US were a single computer hooked up to one (or two!) phone lines and most access was local. Getting access required knowing the phone numbers, protocols and software required to access the BBS and was mostly through word of mouth. Generally if you could get access you must have some connection to existing users and so you were in. Most had time limits so that you couldn’t tie up the line all day. Some communities that has special access to computers or telecom gear tended to be larger. ISCABBS, for example, was a fairly large BBS because of the access to TTY terminals and donated computing power (https://en.m.wikipedia.org/wiki/ISCABBS https://en.m.wikipedia.org/wiki/ISCABBS)