Gnome Shell 3.2 is about to be released. Developers are almost done with this new version, which will support "one click" installation of extensions, a feature that was implemented in the latest version of Gnome Shell (18.104.22.168).
Gnome Shell extensions are small applications that can be installed and executed within your desktop. You may install the weather extension, for example, to add weather information to your desktop with just one click like you do with Firefox or Chrome extensions. The website dedicated to this new feature is still not online (extensions.gnome.org), but it will open its doors very soon.