“The purpose of the Persona, I believe, is to add empathetic focus to the design. Empathetic focus. By focus I mean that the design must be clean and coherent. It is not a collection of features added willy-nilly through the life-span of the product, even if each feature by itself makes sense. Rather it is having a clear image of what the product is meant to be ó and what it is not meant to be ó and rejecting features that do not fit, only accepting ones that do.”