BBS is something like a forum. Exchange of public letters in thematic rooms. BBS knew its best days in the times of the early Internet. Now exists in a half-dead state. There are only traces of the former greatness: su.books archive and a collection of texts on HarryFan CD.

Usenet:

Registration - https://www.eternal-september.org/RegisterNewsAccount.php?language=en

Newsreader - https://www.shemes.com/index.php?p=download

Fidonet:

Архив su.books - http://www.fandom.ru/fido/su_books/

HarryFan Text Collection CD 1.0 - https://archive.org/details/harry-fan-text-collection-cd-1.0

wfido - https://wfido.ru/wfido/?login=1&area=NETMAIL&message=