>>610
You're not wrong, but you don't have the full story. There's no need for the board to be the only data your node has.
https://github.com/ipfs/notes/issues/15
Concretely, every node interested in the same board (on the same BBS protocol and version) would run something like echo 'dqn@ipfsbbs.0' | ipfs block put, and then ipfs dht findprovs <blockname for dqn@ipfsbbs.0> to find other nodes who have done the same.
I haven't actually tried that yet though, so I could still be mistaken in what exactly is supposed to happen.