In 2017 Guentner, Willett, and Yu introduced a new notion of dimension for dynamical systems in the general context of etale groupoids. This theory has seen various applications, for example in the structure theory of the associated C*-algebras, their K-theory and most recently to groupoid homology. I will give an introduction to this theory and its applications before presenting some new results on permanence properties of dynamic asymptotic dimension, its relationship with Gromov's classical notion of asymptotic dimension in coarse geometry, and a refinement of some known applications.