In the following article and supported by a video-tutorial, I'm going to teach you install new extensions that will give more functionality to our spectacular gnome-shell interface.
The method to install a new extension or functionality to our desktop gnome-shell, it is the sea of simple and simple to the most, you just have to look at the video in the header to see the extreme simplicity of the process.
Extensions are tools for install new features to our desk gnome-shell, for example, in the video I show you how to install a drop-down menu for applications, like the old gnome menu but more attractive, this will be a new menu that will be added next to the corner of activities or dash original gnome-shell, and in no case will it replace the original dash if not to complement it.
If you are interested in install new extensions, the first thing you should do, it will install the gnome-tweak-tools, which is the tool with which you will control all aspects of the desktop gnome-shell.
Once installed, you just have to follow the steps of the header video and select the extensions you want to enable or disable from your desktop.
In the website of the example itself you have extensions for all tastes, the bad thing is that the specifications are in English, that's why it is a matter of trying them and if you like them, leave them installed and if you don't, uninstall them.
More information - How to control and modify aspects in gnome-shell, Ubuntu 12.10 "Quantal Quetzal" on ASUS EEPC 1000HE running gnome-shell
It is not true the option to obtain more extensions does not exist