Mailing the story:

Cinnamon is a user interface. It is a fork of GNOME Shell, initially developed by (and for) Linux Mint. It attempts to provide a more traditional user environment based on the desktop metaphor, like GNOME 2. Cinnamon uses Muffin, a fork of the GNOME 3 window manager Mutter, as its window manager from Cinnamon 1.2 onwards