The Seagate Dockstar comes with three USB ports and an additional port for a Freeagent Go harddisk. As I am not using the Dockstar with such a harddisk, I did not use that port. Since the port does not use some non-standard connector but a mini-USB connector found on many devices, it can easily be converted to a standard USB host port using a suitable adaptor. With such an adaptor it works just like the other USB ports.
It is pretty nice for installing a wireless adaptor since it is then aligned vertically.