I loved BBSs, used them from 300 baud on up in Winnipeg. They were great for the local scene, but it was the advent of store-and-forward networking that really blew me away. Mail and newsgroups to and from my home system, through a guy working at an ISP (hi Greg!), and off to the world.
By batching up messages together and sending them in a periodic squirt, you didn't need to tie up the phone line for long. Sending email meant storing it in the spool, and it would go out soon enough when the connection next occurred. Now that I live on a coastal island where DSL doesn't reach everywhere, I wonder if this tech is still useful. Ditto for when things go down (tree on the wires, this time of year), would love to see a robust, distributed alternative. Maybe a mesh net?