I have for many years asked why modern laptops have a PC Card (PCMCIA) and more recently the ExpressCard slots. Years ago, the PC card slot was the only way to add functionality like a WiFi card, and sometimes even basic networking, but today (and for many years) most laptops come stacked with so much built in (networking, modems, Wifi, USB, FireWire, multi-monitor video out) that the inclusion of an expansion slot seems just like a waste of money and space in an environment that has limited space to begin with.
Despite the limited usability of the slot, nearly all laptops continue to come with the ports, even the MacBook Pro includes an ExpressCard/16 slot despite the fact that it has the sort of port connectivity that would make most desktops blush.
I've had 6 different laptops over the last 6 years, and I don't think I've ever actually used the PC Card slot, or even seen a device for the ExpressCard slot in my MacBook Pro that holds any kind of interest at all.
Until today, when I came across the Transcend 16GB SSD card for the ExpressCard
slot. The ExpressCard slot is fast enough that you could use this for swap or a scratch disk (particularly useful for us Photoshop users) and take advantage of a large quantity of fast and low-power storage.