snail mail
Etymology: Scott Adams, creator of Dilbert
(n) conventional mail in which a letter or package is physically delivered by a postal service, esp. when the object mailed could have been sent electronically via email/e-mail and arrived at the destination instantly
Paranoid about "hackers" spying on him, my boss insists on sending all correspondence via snail mail, which means I can't use my spam filter to ignore him.