Useful for large tasks,
- Newsletters
- Seach indexing
- PDF Generation
http://framework.zend.com/manual/1.12/en/zend.queue.adapters.html
http://www.justincarmony.com/blog/2012/01/10/php-workers-with-redis-solo/
http://help.pagodabox.com/customer/portal/articles/430779