Although it's based on the Netbook edition (as far as I know) yet it has a lot of different aspects in comparison. For instance, Netbook edition used to have a composting window manager (written in GTK+) called Mutter. But with Unity they decided to replace it with Compiz instead. And also the completely redesigned the Application launcher and its behavior in Unity as well.
But for some reason, if you still would like to have that old Netbook launcher in Natty Narwhal... using Mutter, then our friend DoctorMo has been kind enough to do that as well. What a cool doctor after all :). And remember you cannot run this in Unity Shell (the default 3D interface)... only for Classic Gnome desktop under Natty Narwhal.
If you want to install 3D Netbook launcher in Ubuntu Natty, then paste the below command in your Terminal window. Have fun with it :).
sudo add-apt-repository ppa:doctormo/netbook-launcher
sudo apt-get update
sudo apt-get install yeold-netbook-launcher