"The big news at the Ubuntu Developer Summit? Moving to
Unity as the default interface for Ubuntu Desktop with Natty
Narwhal (11.04), rather than GNOME Shell.
"Earlier this year, Canonical representatives had to deny that
they were forking GNOME with the work on the Unity interface.
(Quick disclaimer, I'm a GNOME Member and help out with GNOME PR.)
Unity is a Canonical-sponsored project that was initially delivered
for the Ubuntu Netbook Remix. GNOME Shell is the interface being
developed for GNOME 3.0, which was delayed to spring 2011."