This is true, but it's no different than the cookies that are currently stored/tracked on these computers.
To stretch my idea even further, if there is a will there is a way. All they have to do is create a simple little program that will change the system's IP address every time a new user logs on. Say a window will prompt for the login/password, and the login will be the IP. This will of course wreak havoc on the network structure, but with the advance of wireless networks and entire cities getting ready to go wifi, this is looking more and more like when cell phones first appeared on the market. I'm sure they can come up with routers that will send traffic from each IP to its appropriate router over wifi.
Aga>> If the government really wants to track people's online usage