Just like Microsoft with Windows 8, Canonical is pushing forward with ensuring ARM-compatibility for future versions of Ubuntu. In order to do that it needs a proper build environment and hardware to allow contributors to submit and build the 20,000+ packages that make up the Linux distribution.
As with anything to do with Ubuntu, it's up to the enthusiastic individual to come up with and implement the solution to a problem. David Mandalla of Canonical was tasked with creating an automated Ubuntu ARM build machine, and the resulting solution definitely registered on our geek radar.
The required machine had to be capable of supporting package builds from multiple users in a clean build environment. On top of that, it needed to be relatively cheap to create in the first place. Mandalla therefore decided on a custom build using PandaBoards.