This blog post couldn’t make its point clearer.(http://radar.oreilly.com/2009/03/continuous-deployment-5-eas.html)
It’s a process whereby all code that is written for an application is immediately deployed into production. The result is a dramatic lowering of cycle time and freeing up of individual initiative. It has enabled companies I’ve worked with to deploy new code to production as often as fifty times every day.
Continuous deployment is controversial. Most people, when they first hear about continuous deployment, think I’m advocating low-quality code or an undisciplined cowboy-coding development process. On the contrary, I believe that continuous deployment requires tremendous discipline and can greatly enhance software quality, by applying a rigorous set of standards to every change to prevent regressions, outages, or harm to key business metrics. (This criticism is a variation of the “time, quality, money – pick two” fallacy)
If I may add, open source has been this way for many many years now.