The Yet Another Window List “YAWL” extension has been created, by the Gnome Shell developers. It aims both desktops with Gnome Shell and touch screen users, so it may be a good thing for the future Ubuntu Phone users.
Gnome Shell is powerful because of this extensions, that add features to the one using them. YAWL brings an experience similar with the Microsoft Windows 7 taskbar. YAWL is compatible with Gnome Shell 3.8.
Among other features, it allows the users to preview a window by hovering its thumbnail, helps the user rearrage the task bar and change the thumbnail size, and many other things. A bigger list of features can be found here.
To install the YAWL extension, just go here and confirm the installation.