Media Temple uses the OpenVZ virtualization system and I have quite a few Media Temple servers under Chef management. The one thing that has made management difficult is that by default during a Chef run ohai returns 127.0.0.1 as the default IP address which means I cannot run knife to execute commands from my workstation.
I use Chef to manage and provision new staging and production servers in our company. It takes a lot of the headache out of managing multiple servers and allows me to fire up new web & data servers for our projects with ease. I have several cookbooks that I use to configure servers and to setup/configure websites. In a nutshell, it's rad, and website deployments have never been easier.
It was brought to my attention at the office that a few of our recently launched websites had publicly exposed .git repository information. Unscrupulous users could use the exposed data to pull down the entire commit history, giving them unfiltered access to what is basically the blueprint for the website.