Ok, this is getting silly, the race to be the smallest *insert random gadget category* has got to stop at some point. SD cards is probably at that point with the micro-SD card, but for USB memory drives, I think Sandisk just hit the extreme with the Cruzer Fit.
It's very small which makes it very portable; The small metal loop makes it easy to attach this to a keychain or turn it into a cellphone charm; Has an LED light bulb to monitor data transfer activity; Comes with a plastic cap
Slow data transfer speed; It's very small; can be easily misplaced