It is a flavour of Ubuntu (like Kubuntu or Xubuntu) that is basically the same desktop environment as Ubuntu (a GNOME desktop) and a very strict set of restrictions on the licences of code and content. This means that we try to strip out ANYTHING which is not modifiable and redistributable, including firmware, PDF’s, video footage, sounds etc. We are trying to apply the FSF “rights” definition to everything in the platform. Gobuntu will not correctly enable much hardware today - but it exists as a banner for the cause of software freedom and as a reference of what IS possible with a totally rigorous approach. The goal is to make it a real point of pride to be able to run Gobuntu on a laptop or desktop or server, because it means that all of the stars have aligned to ensure that you have complete freedom to use that hardware with free software.
What in the world!? No proprietary software? That'll make the distro basically... useless. PDF is one of the most common file formats available on the internet, and WMV-AVI/ MOV-MP3-MPEG/ and RAM are much more popular media formats than OGG.