  We discuss the derivation of the trace anomaly using a non-local effective
action at one loop. This provides a simple and instructive form and emphasizes
infrared physics. We then use this example to explore several of the properties
of non-local actions, including displaying the action for the full non-local
energy-momentum tensor. As an application, we show that the long-distance
corrections at one loop lead to quantum violations of some classical
consequences of the equivalence principle, for example producing a frequency
dependence of the gravitational bending of light.
