Definitions for "Chain letter"
A letter that explicitly directs the recipient to distribute copies of itself. Some modification of the letter may be requested before making copies, often the updating of a list of senders.
A pyramid scheme in which you send money to a person at the top of a list, add your name to the bottom, then send that list to acquaintances and convince them to do likewise. A common, now infamous, one on the Usenet was started by Dave Rhodes. Chain letters, even those which purport to 'sell' mailing lists, are prohibited at over 90% of Internet sites, and if propagated by e-mail or news will likely cause you to lose your account.
A letter that invites the recipient to pass the letter along to others. Chain letters often contain the threat (implicit or explicit) that if the letter is not passed, ill fortune will come to whoever breaks the chain. The Internet has made sending chain letters easier than ever, as many recipients can be targeted at once.
Keywords:  scam, stuffed, mailbox, quick, rich
a "get rich quick" scheme and a work at home scam that promises that your mailbox will soon be stuffed full of cash if you decide to participate