The beginning of the 2013 year marked a reference point for Ubuntu, the year when Ubuntu enlarged its horizon and vision, namely, the addition of Ubuntu for phones and Ubuntu for tablets to Ubuntu's family of interfaces.
Just like solid-as-a-rock security, heavily-tested and designed user experience, pixel-perfect polish, etc, converged experience is written on Ubuntu's forehead.
Essentially, the developers are approaching Ubuntu as a numerous full-of-members family, rather than from an only-desktop point-of-view.