In Linux and other UNIX-like computer operating systems, the root account is the administrator account. A user with root privileges can perform many tasks that a standard user account cannot. In current editions of Fedora 17, the idea of a disabled root account is a foreign one.
But come Fedora 18, the next stable release, the root account will be disabled by default. It is one of the many new features of Anaconda, the Fedora system installation program. That at least is what you see in the just released Fedora 18 Alpha.