[rabbitmq-discuss] Groking the point of queues in topic exchanges

[methodin]

So when I was originally mapping out how to design an implementation
of RabbitMQ I assumed that an exchange could route messages to queues
and workers could consume solely off one of the queues. When I added
two queues in I found out that the message will get sent to both
queues and those both workers.

So I implemented a topic exchange and route to queues based on routing
keys. I am now, however, at a loss in figuring out the point of the
queues in this system as I could just as easily map 4 different keys
to the same queue vs. routing each one to their own queue. Is there a
large difference here? Should I be aiming for one approach vs the
other?