Related Clues:

• It's supposed to be circulated
• Illegal mailing
• Possibly a type of mail and vice versa
• Sequential correspondence
• Money-making scheme suggested by character on links?
• Cascading correspondence
• Fraudulent scheme to place restraint on tenant
• Fast-spreading communication
• The clarinet (anag.)
• Train landlord in extended communication
• Bond character that starts a pyramid scheme?
• Mail meant to be passed on
• *Thing you shouldn't pass on
• Passed-along missive
• Psst! Don't pass it on!