It's probably all old stuff. There was a time before the internet was common that art like this was the norm in the online world (not just sexual stuff).Some people have entirely too much leisure time.
Are there BBS's still running? MAkes sense that some of those diehards would dismiss the internet as 'too much work' or something like that...I just had flashbacks to when I was a teenager...operating a BBS system out of my house...and art like this was the reward for the end of the ''Door programs' (online games of the 2400-14,400baud world) back in the day...circa 1989.
Cheers