Not sure if already mentioned, but I just saw a pic of a WiiU demo station that clearly showed it was based on Ubuntu software. Plus Nintendo's site has been updated and contains this:

Hmmm. I wonder what this means for Homebrew stuff.

Homebrew is already running on the Wii U. Its running on the Wii OS though not the Wii U OS.

The download just contains some source code files for the Browser and XML parser.  Looks like they made some modifications to support the GamePad (e.g. inputs and video playback), the CPU, etc.  As for the XML library I am not sure what they changed, but that is such a generic function that it couldn't be a major difference.

I wonder whether the Wii U is really running Ubuntu or could it be just the kiosk?

so when you are booting up WiiU it says Ubuntu instead of Nintendo or WiiU etc..?

or is there an option to boot into Ubuntu ?

They have to publish any modifications they made to the Ubuntu or other open code they used, but it's definitely not all of the Wii U system software because otherwise the DRM scheme would be useless.

If that Open Source code is just in reference to the browser, then yeah, its very likely it was just the demo kiosk and not the WiiU itself.

Neither.

The Ubuntu logo isn't in the browser. If the actual Wii U software is based on it they better publish that source code as well.

I never said the ubuntu logo was in the browser. I was saying that if the source code he downloaded was only in reference to the browser stuff (and therefore not what would be required for Ubuntu open licensing release of code), then its likely the WiiU OS is not based on Ubuntu.