When investigating this question, I discovered that many GNOME applications' packages depend on the libunity9 package.
If I try to uninstall libunity9 on Precise, it tries to uninstall lots of GNOME applications:
how could the ubuntu developers possibly think that would be a good idea? Ubuntu is starting to be more and more like windows :(
The libunity9 package is described as:
binding to get places into the launcher - shared library
libunity is a shared library to be able to interact with the launcher and add places in Unity environment.
This package contains shared libraries to be used by applications
So obviously it's a component of Unity. It is odd that GNOME applications depend on Unity. Since Unity is an Ubuntu-specific addition, upstream GNOME apps shouldn't be depending on it.
Why these dependencies?
.msifiles are not executables, they correspond to.debfiles), installed software is kept track of in the registry, and you can repair and remove installed packages in the control panel. Windows doesn't call it a "package manager," but it is one. The central feature of most package managers in contemporary GNU/Linux OSes that Windows lacks is that Windows doesn't have a facility like APT for downloading packages from the Internet and automatically resolving their dependencies. – Eliah Kagan Mar 22 '13 at 11:01