Tens of Thousands of Google Employees Use Ubuntu
Goobuntu is a Linux distribution made by Google and based on Ubuntu
During the Ubuntu Developer Summit for Ubuntu 12.10 (Quantal Quetzal) that took place in Oakland, USA, Thomas Bushnell from Google talked about how Ubuntu is used by Google developers.It appears that Goobuntu is a Linux distribution, based on the LTS releases Ubuntu, used by tens of thousands of Google employees, including managers, graphic designers, translators, software engineers, system engineers, people who wrote the original Unix, people who don't know what Unix is, some of the best programmers in the world, and others.
Google makes no modification to the Ubuntu default user interface, they use a centralized administration with apt and puppet, a LDAP-based user database, and automated release testing.
For more details about Goobuntu and how Ubuntu is used inside Google, take a look at the 1 hour video of Google's presentation, posted above.