Definitions for "private message"
a message sent from one member to another through music
an email sent via the system from one member to another without the sender or recipient knowing each other's email address, or any other member knowing about the message
an encrypted message whose text is hidden from view, giving you an option not to store the message
Keywords:  viewable, folks, invited, topic
a private topic viewable by only the folks invited to the PM
Keywords:  conversation, people, two
a conversation between two people in private