What role does open source play in cloud computing innovation?

http://gigaom.com/2012/09/22/what-role-does-open-source-play-in-cloud-computing-innovation/

/ open-source cloud management tools Eucalyptus,CloudStack OpenStack OpenNebula lower lowering barrier to entry open source building designing cloud open-source software stacks customizeability does what you need it to do licensing fees /