More specifically, PSTN is a public, switched, telecommunications network, in which each communication occurs over a direct, and until recently physical, circuit. The "switches" refer to how those circuits are set up and broken down. By contrast the Internet is packet routed; each data packet is routed across the network by the best available route. Users don't have dedicated circuits (though there are dedicated addresses), but rather data from multiple communications is commingled on common transmission channels.
There were BBSes which you'd call directly (the job board DICE ws initially a BBS), but BBS != website. Similar in ways to today's SPAs though.
https://www.techopedia.com/definition/1704/point-of-presence...
The backbone connectiin was TCP/IP, not PSTN. There are no distance charges, only bandwidth, generally at 95%ile peak "burstable" billing: