My 3 examples:

@Computer
@HomeComputer
@E-mail
Why? Because the scanner and the laser printer are at home... @Computer is any of my computers, including my netbook that I carry everywhere.
E-mails are trickier, because maybe I need to send a file residing at my home computer, if not I can send an e-mail from my BlackBerry.

Greetings from sunny Baja, Mexico...