I am absolutely zero when it comes to technical
topics, but I can hardly
imagine that it be impossible for servers to exclude single computers -
regardless of the User Name apllied.
Consider this an education. We cannot idenfity individual computers.
Computers just don't send out their processor's unique serial number with
every HTTP request, or anything like that... and if they did, they might
just be faking it. Any form of ID 'cookies' and the like can be erased.
The IP address is really the only thing that can't be faked. We can only
identify individual IP addresses. On the Internet, many computers may
share an IP address (ever hear of 'proxies' and 'NAT', 'Network
Address
Translation'? Look them up on Wikipedia) and many computers can jump
around between many IP addresses (dial-up networks and AOL users, in
particular). The end result is that we cannot block them by individual
computer: we can only block them by their IP address, and (if the IP
address is variable) by their internet service provider, and there are a
*lot* of people out there who can be affected by such a block,
particularly in the case of AOL.