[no subject]

Platform, ie stuff that we want to be used in other modules
  The platform splits into stable (the current platform) and unstable
(things like gstreamer, gnome-desktop, libsoup, telepathy etc)

Desktop, ie the desktop shell itself, plus 'appendages'
  This includes things that are 'part of the desktop' instead of
standalone apps, like control-center, gnome-media, gnome-keyring

Apps, ie standalone applications that use the platform modules and run
on the desktop, but are not part of the desktop itself: epiphany,
empathy, vino, etc etc

Nautilus is an interesting case, since it may well move from 'Desktop'
to 'Apps' in the transition from gnome 2 to 3.