Just to refresh. At this point there is a huge difference between Continuous Integration (CI) and Continuous Delivery (CD). While most of posts above described CD I'll try to show how CI extends now CD definition. Having all the tools needed to build a package and deploy new version of app automatically is a crucial part of CD. Adding to that test automation (based on three level verification: General Health-check, Detailed Statistics and Historical entries) and a proper governance you're creating a really good piece of CI. Only because of such an extended definition building extraordinary cloud tools is possible. Think about muleESB or esbeetle.com. For both of them CI is something natural although only the second one is supporting both ESB and ETL components.
I hope that it was helpful.
