Merriam-Webster definition of HOAX:
Pronunciation: 'hOks
Etymology: probably contraction of hocus
Synonym: dupe
  1. to trick into believing or accepting as genuine something false and often preposterous (emphasis added)
  2. an act intended to trick or dupe
  3. something accepted or established by fraud or fabrication
The Internet community has endured a wave of e-mail hoaxes and pranks, exploiting users' unfamiliarity with how the Internet, and computer systems in general, work. With the phenominal growth and popularity of the Internet, more and more new users are "getting online" and becoming targets for pranksters. "Ancient" myths, like the Neiman Marcus cookie story, are just waiting for a critical mass of people who have not been exposed, so that they can go streaming across the net again. There is no technical solution to this problem. Even when users become experienced enough to be able to tell a silly message when they see one, anyone can sometimes get suckered. It seems that all users of the Internet will have to put up with a certain amount of nonsense.
These e-mail hoaxes are every bit as insidious as any other e-mail virus, but not as destrctive. They do their damage by slowing down ISP mail servers, clogging up users' mail boxes, and wasting the readers' time. They act like other computer viruses, only they use people as the method for infection (social engineering). Users of the Internet must learn to be skeptical, and think carefully before spreading a message to anyone. There are some simple things that can be done to avoid being a carrier for these hoaxes.
If you get a message that seems like it should be shared with lots of people, DON'T SEND IT unless either you know that the message is true, you can authenticate the identity of the sender, or you know the sender personally, and know that they would have written the message. The more urgent it sounds, the more skeptical you should be.
If you really want to send it, ALWAYS CHECK WITH THE ORIGINATOR before forwarding it! This is the best way to tell a hoax or a prank. Just reply to the first sender, and ask them if it is true. If they can't tell you, then don't send it! Most pranks and hoaxes have forged headers and signatures, and when you try and verify the validity of the message, you will find that the address is not valid. Even if the originator is the prankster, and tells you to go ahead, at least they can be caught and dealt with. If this seems like too much of a bother, then it is not that important and you should not send it.