If they're e-mail messages, just treat them as Junk E-mail. There's no point
in trying to get everyone to stop sending you junk mail. It's a thankless
task. Set up your Junk Mail filter to access Safe Senders Only and people in
your Windows Contacts. Let everything else go to Junk E-mail.
Responding to junk e-mail messages to try to get off their list often just
results in more junk mail, because now they know they're getting through to
you address.
