So after reading http://www.migueljacq.com/content/drupal-deployments-workflows-version-c... I headed for the dev playground and grabbed a copy of aegir.
Well, I also wanted to test something else in the process so I grabbed omega8cc's excellent script Barracuda, from http://github.com/omega8cc/nginx-for-drupal and a fresh shiny VPS server to test this installer script.
The principle - and I apolgise profusely to all those fine folks working on Aegir for getting this wrong - is that you can manage a number of drupal sites from another drupal site. You can create, disable, delete, clone, backup etc a drupal site with a few clicks and a form.
Personally, I think it's a better idea to understand the scripts you're using rather than relying on the scripts without comprehending what they do, but if you're looking to try Aegir I highly recommend grabbing a cheap vps and firing Barracuda.sh.txt at it and having a good look at the structure that's created and what the scripts have created for you.
Once you understand what's happening under the hood (as our Pondian friends would have it) you'll probably STILL end up using the script since it is so useful and well done. Efficient automation is a thing of beauty!