  We discuss the fluctuation properties of diagonal matrix elements in the
semiclassical limit in chaotic systems. For extended observables, covering a
phase space area of many times Planck's constant, both classical and quantal
distributions are Gaussian. If the observable is a projection onto a single
state or an incoherent projection onto several states classical and quantal
distribution differ, but the mean and the variance are still obtainable from
classical considerations.
