Paul-
I don't know anything about Portal, since I'm not on it (nor can I be
on it, it's not local to Toronto. ^_^)
FidoNet is a hobbyist network, linking BBSs all over the world. They
call each other to exchange messages on bases that they have in common.
(This usually takes place late at night, when phone rates are lowest)
It's a lot like SI$, but messages take longer to get from place to place.
(I find that I can chat with someone on the other side of the continent
with propagation delays of between 3-5 days.)