1. A system for the mass customization of a software artifact to create one or more variants of said software artifact for different products in a product family, comprising: a processor; a computerized software engineering tool used to design and create one or more software artifacts, said software artifacts having common model elements, and said software artifacts also having one or more model element automatons, wherein each of said model element automatons serves as a proxy for a real model element that varies between products within a product family; and a fully automated computerized product actuator used to provide a predefined feature profile that specifies desired features for a variant of said software artifact to each of said model element automatons, thereby automatically instantiating a real model element in place of each said model element automaton to create said variant of said software artifact.