I discuss general properties of supersymmetric Anti-de Sitter (AdS) backgrounds, in particular regarding their moduli spaces and domain walls. I argue that lower-dimensional gauged supergravity is a strong tool to understand supersymmetric AdS backgrounds, independent of the compactification manifold. I show how the moduli space can be determined and explain what this means for the dual conformal field theories. In the last part I comment on supersymmetric domain walls and their dual interpretation as supersymmetric RG- flows.