Speaking of widely used standards:
FBB forwarding IS the second most widely used standard for BBS message
forwarding, since most other BBS systems have long dissappeared, their
places being taken over by forums and social networks.
The only surviving standard is, to my knowledge, FidoNet with about 2000
nodes.
And running a citadel is a little overblown, taking in account that their
interface is much more console oriented, a dumb terminal not being enough.
My opinion: If you need an AX25 connectivity, then you need something
oriented towards it, like FBB, NOS or a PMS. If you want to go the fast lane
set up a forum, a mail server and possibly an IRC server.
By the way: Anyone interested in reviving the old HamIRC network?
73s de Marius, YO2LOJ