In my case, Emacs in an ssh window got pretty confused until I added something to my .emacs file, but that's another story. I'd like to be able to hook up my laptop with another. It's quite interesting sometimes to link two systems together to share files or play a networked game or just chat for some nerdy reason. One way to do this is to use a parallel-port connection, but it's very slow. A modem is even slower.
Ethernet is best.
It's so much faster than the other connections, and the stuff you need to make it work packs much lighter. Get yourself a couple of Ethernet PC cards and a cross-connect cable. They look just like Ethernet cables, but they are wired a little differently inside, so you don't need a bulky hub between them. The real trick here is choosing a Linux-compatible PC card that fits in your laptop. Other cards are too long for some card slots, so they can't work for everyone.