During the development of software we use these steps design, develop, test and deploy. Agile or not, these steps always exists. Different environments for the different parts. During development you need a development environment and that is usually local. Testing is done on a Test environment and most of the time this is centrally maintained. On Production we just deploy and previous steps validate this is without errors.
But sometimes a deployment (production or test does not matter) needs some processes to light up the environment a bit. For example the first call to a website always takes some time. Not real strange because of caching and loading the stuff. But in Production you users will notice this delay too and they don’t want to wait.
For this reason it would be handy, if you could preload or precach stuff right after the deployment. Your users won’t have to wait for this.
With Microsoft Azure Cloud Services we had a Staging environment for this reason. On this Staging slot you could touch enything to get the first delay away. After this you swapped Staging to Production.
With Microsoft Azure websites there was no Staging. But now it is also available for Websites. It looks a bit different, but it works like Cloud Services. The Staging slot is not default available.
En make Staging Production is as easy a abc.