I know that most popular BBSes were run by telephone companies, and were analogous to modern "chinese superapps" or do-all social networking sites like Facebook or VK, in a sense, not only you could use the bullet-in board forums or send email to other phone company subscribers, but also access banking services, post dating/sale ads, look at address catalogs. Prestel in Britain, Minitel in France, CompuServe in USA, some analogs in Canada and Sweden, canadian one had special markup that allowed vector graphics, it was also used in some information terminals like ATMs. Minitel had some sort of BBS-hosting where businesses could have a dedicated phone number with their BBS hosted at phone company locations.
Local hobbyist-run BBSes were made possible due to free calling for certain city areas, AFAIK, in United States, or because every user knew phreaking and could get free calls from anywhere. Fido nodes exchanged inter-city echomail over nights when calling fees were much lower than during day. Later Fido client software also allowed downloading mail for offline reading, and terminating the connection to save money and free the phone line. Something most modern forum systems severely lack, due to them being webshit, asides from email of course.
CompuServe had world's first live chatroom on their BBS in 1980, which predates IRC by 8 years. Not counting UNIX "social" system commands that predate even this one.
IIRC, Eastern Europe didn't get into this computer business until 90