Routing Key
With RabbitMQ a routing key can be used to route the messages to a specific queue or filter the messages in a topic. See also the routing and topics tutorials on the official RabbitMQ web site.

Silverback offers a convenient way to specify the routing key, using the RabbitRoutingKeyAttribute.
public class MyMessage : IIntegrationMessage
{
[RabbitRoutingKey]
public string Key { get; set; }
...
}