Ubuntu Unity is Canonical's netbook UI, introduced in Ubuntu 10.10. It is, by far, the worst netbook graphical shell I've ever used: extremely slow on Atom-based netbooks, clumsy, inconsistent and of arguable 'retro' æsthetics reminiscent of 1990s NeXTSTEP and clones, only with half of the usability those had. Needless to say, vanilla GNOME with Docky as a launcher is --- in my opinion --- a vastly superior and usable solution for both netbook and desktop use, until something better (viz. GNOME 3.0) comes along.
So, it seemed almost like a joke when Shuttleworth announced earlier today, as reported by the linked
Ars Technica article that Ubuntu 11.04 won't feature the GNOME Shell, but
Unity as the default shell, for both the netbook and desktop editions. Pathetic, really, no matter how you slice it.