is there any real use for it? seems a bit obsolete. i had a firewire cable from an old ipod i thought id try with my iphone but its a different shape and any cables i find for anything else are that old shape.
External HDDs can be connected to it, many still have use for those, even in the age of USB 3.0 and Thunderbolt.
There are also other external devices using Firewire, like signal input/output converters for video and audio, which cost more than just 30 USD to be replaced by a Thunderbolt or USB 3.0 alternative for another 300 to 900 USD upon the purchase of a new 2012 Mac.
Firewire, as Thunderbolt, also allows daisy chaining Firewire devices, up to 63 of them (Thunderbolt only allows 6), and I often have 8 to 12 FW 800 HDDs connected to one Firewire 800 port on my Mac.
Lots of hard drives out there have FireWire 800 connectivity. It is faster than USB 2.0 but slower than 3.0. Some video cameras use FireWire as well. In terms of cables, cheapest ones you can find are @ Monoprice.