edit: I may have spoken too soon. I plugged one of my WD portables into it and it gave me the blinking-light not-enough-power signal. I wonder if perhaps my brand new self-powered usb hub is, perhaps, not supplying normal power to the ports.
edit: borrowed a cable from scott_t_s, and tested. The WD drive works fine in the hub with a different cable between computer and hub. the superdrive does not. so, a) the hub is shit and b) the superdrive is a bitch.