RabbitMQ is used in several example applications and real case studies. Three example codes demonstrate: 1) the RabbitMQ tutorial using request/reply queues, 2) RPC using correlated messages, and 3) Celery's distributed task queue using polling. Case studies show RabbitMQ for: 1) message passing between Zenoss daemons, 2) Nova controller RPC, 3) Instagram's task queue with Celery, 4) MercadoLibre's service bus architecture, and 5) Indeed.com's distributed crawling. RabbitMQ provides reliability, scalability, and asynchronous messaging between distributed applications and microservices.