When you have as many users as we do, you become experts at queueing background tasks pretty quickly. We've used all the biggies: RabbitMQ, DelayedJob, Resque, Beanstalk and we're going to tell you all about 'em.
Merb was an alternative to Rails, whose hey-day was early in the Rails 2.x Era. It was announced that Merb would be merging into Rails 3.x and that Merb users would have an easy upgrade path. That was not the case. Now it's time to flee. Our hope is that sharing our decision making process might help other Merb users.