Quora discussion: http://www.quora.com/RabbitMQ/RabbitMQ-vs-Kafka-which-one-fo...

RabbitMQ developer on the kafka-users list: http://mail-archives.apache.org/mod_mbox/kafka-users/201306....

SO discussion on several queuing systems: http://stackoverflow.com/questions/731233/activemq-or-rabbit...

Quora link where you don't have to register/log-in: http://www.quora.com/RabbitMQ/RabbitMQ-vs-Kafka-which-one-fo...

It keeps all messages in a log(sorted) and each client has a position of where they are in the log. So they can restart some parts, or skip some. This makes it very fast.

And it has sharding, which no-other messagequeue has (i think).

RabbitMQ supports sharding via exchanges