BBS have quite a revival with LoRa and other similar technologies emerging. Basically, people put their own radios at home and use them for messaging and yes, for BBS. Some networks, like Reticulum, also support virtually any connections, including your regular Internet one.

Check out Reticulum (might take some time to wrap your head around it, hit me up if you need any explanations), and also MeshBBS if you run on Meshtastic/MeshCore networks.

Here's an example screenshot of a Reticulum BBS site:

Telnet

Telnet support has become highly unusual in new applications, though amateur radio operators and multi-user dungeons do continue to utilize it. Telnet is a popular protocol to connect to the roughly 1000 Bulletin Board Systems (BBS) that are on the Internet.

http://www.tim.org/

Isn't the linked site a bbs? Or is it just in the name but doesn't make it so 🤔

Telnet!