Prediction and measurement of vibration power flow in structures are both important for locating vibration sources and sinks and for confirming vibration propagaing paths. From the point of view of noise and vibration control in industries, the method is very important for practical reasons. Consequently, it is essential to address the state of the art of the method, its effectiveness and limitations. Vibration power flow methods or structural intensity techniques are reviewed and compared in this paper. There is a particular focus on flexural waves, but in-plane waves are also considered. Both experimental and numerical methods are put forward. Likely future trends of structural intensity are also discussed. The anticipated areas of interest include complex structures such as build-up edges, stiffeners, and modified geometry of beams and plates.