Our understanding of the rich and complex motion of macromolecules has developed rapidly in recent years, particularly in the entangled regime. In this paper we highlight examples of research that has exploited our detailed picture of macromolecular motion. These studies encompass a broad range of areas in polymer physics, including neutron scattering under strong flow, tear properties of oriented polymers, flow-induced crystallisation and single molecule theology of biopolymers. In each case molecular modelling plays a key role in understanding the observed phenomena. (C) 2007 Elsevier B.V. All rights reserved.