1. A method of automatically populating a message with one or more selected addressees, the method comprising: selecting a content item to be distributed via automatically addressed messages; identifying multiple target recipients of the content item; and upon notification of generation of a message comprising the content item by a message initiator, operating one or more processors to: identify, within a network comprising the message initiator, a sub-network comprising first degree connections of the message initiator; identify a minimal set of the first degree connections through which the message initiator is connected to the target recipients; select as addressees one or more of the first degree connections that have not previously received the content item; and automatically address the message to the selected addressees.