The Commodore 64 boards had a quite a few BBS systems from pretty spartan 6485-BBS, Compute's Gazzette BBS (yeah they even had a magazine type-in BBS: Dec'84 & Jan'85), up to more advanced ones like Color64/128, C-Net 64/128, and Image BBSs - the high end ones used either a bunch of 800k 3.5" drives or hard drive (comparatively expensive but was worth it for speed and storage), or RAM drives.
Near the peak of Commodore BBSs some publishers and SysOp worked up their own Commodore BBS networking schemes where BBSs could exchange emails and forum postings (like FIDONet, but specific to Commodore), there was even a couple multi-line Commodore BBSs, and a few got the different makes of BBSs cross communicating as well. Such things were a labor of love, as us SysOps footed the long distance bills to exchange messages on top of the cost of an extra line, hardware, etc. (the automated exchanges happened during lower cost calling hours, like 2am.)
Now a days there are still a few that either held on or have started new Commodore BBSs - with most BBSs now being accessible via telnet (though I hear there are a couple dial up ones out there).
Of course there was a bits of rivalry between computer models as well as BBS brands...
Any former SysOps/Callers out there?
Me: Joe Commodore SysOp of Silicon Realms BBS 1987-2004