Forgive my ignorance, but I'm from planet PC.
What Fejas was referring to, it seems, was using Firewire for an internet connection. Lots of other peripherals can attach directly to your computer via a firewire cable though, like printers and scanners and such, and if you don't have the right port, you could be screwed.
It seems like older (Firewire 400) devices can be plugged into the newer Firewire 800(1394) ports, with a special adapter, but I don't know if you can plug the newer (800) devices into the older (400) port that's on your computer. If your computer takes cards though, you can buy the new firewire cards for cheap and give your computer the capability to run these devices.
Don't quote me on that.