A simple yet salient detail about fanout exchanges…
Perhaps it was just my inattentive reading, but I was under the impression that a fanout exchange itself would transmit a received message to every host connected to the exchange. Au contraire, a fanout exchange will transmit a received message to every queue bound to the exchange. If hosts connect directly to the exchange, the exchange will deliver the messages in a round-robin fashion, which will be confusing if you’re expecting “broadcast” behavior.