I think this clarifies things: "There is going to be some questions about this decision in relation to GNOME. I want to make something crystal clear: Ubuntu is a GNOME distribution, we ship the GNOME stack, we will continue to ship GNOME apps, and we optimize Ubuntu for GNOME. The only difference is that Unity is a different shell for GNOME, but we continue to support the latest GNOME Shell development work in the Ubuntu archives" From: http://www.jonobacon.org/2010/10/25/ubuntu-11-04-to-ship-uni...

It doesn't seem like they make that mistake at all:

It will be the first version of the OS not to ship with the Gnome shell as the default UI. Gnome will continue to be the underlying framework, as Unity is based on it, but the interface layer will look nothing like Gnome.