Imagine in a house or a company with two or more pc's. One (the server) is a Dual core, x3, x4, whatever and the others (clients) are an old machine.
The idea is give at login screen the possibility to login the user of the old machine to the faster machine and use the faster resources of the server.
Of course, that server should be configured adding users, deny, remember options. But I dont if it should be at firewall or the users panel or parcially both.