Anonymous remailers send electronic messages without the receiver’s knowing the sender’s identity. For example, if a cybercriminal wanted to send an anonymous message to a target, instead of emailing the target directly, the initiator could send the message to a remailer (an email server), which strips off the identifying headers and forwards the contents to the target. When the target receives the message from the perpetrator, though he or she can see that it came via a remailer, he or she cannot determine the actual sender. During his term in office, President Bill Clinton reportedly received email death threats routed through anonymous remailers.
Schell, B.H., Dodge, J.L., with S.S. Moutsatsos. The Hacking of America: Who’s Doing It, Why, and How. Westport, CT: Quorum Books, 2002.