There are many different queuing systems available like Kafka, MSMQ, RabbitMQ, Amazon SQS etc. Azure Service Bus Brokered Messaging is a queuing system that is a scalable and feature-rich messaging service hosted in Windows Azure, or available as part of the Windows Azure Pack in your own data center.
Message queue provides an asynchronous, decoupled message communication between two, or more, applications. The producer can submit the message to a queue with a guaranteed delivery to one or more consumers. This decoupling enables applications running at different times to communicate across heterogeneous networks and systems that may be temporarily offline.