:') Quick, before the "Dell was making this five years ago" crowd arrives. ;'D
Dell was making this five years ago.
Well, no, but they did offer the utilities to make their own USB flash drives bootable with another OS, primarily DOS, about 2 years ago. You could use those utilities to load up a flavor of Linux, if you wanted. It's pretty straightforward.
That's what this is, just a normal USB memory key, except they've pre-loaded an OS on it. There's no processor on the USB key, so it's misleading to call it "a computer on a stick."
I've been working, off and on, to get Windows XP to boot from a USB key (and now USB hard disks) because most of the utitlities the techs at my company work with need to run there, not on Linux. The problem has been that the first things XP does when it boots is reset the USB interface. Kinda brings the entire boot process to a screaching halt. XP SP2 is supposed to allow you to bypass that, but I haven't had time to go back to this since that came out. The closest I got to getting XP on a USB device to boot was to set up a RAM disk first, move the kernel there and then continue the boot process. It works, but it's a pain in the behind to set up and maintain.