Deeply embedded in product development culture is the notion of a “feature” — often taken to be an atomic unit of functionality. Development culture (and product management culture, for that matter) seems obsessed with features. We prioritize them, count them, and try to optimize the number of features we implement. But the very notion of a feature is incomplete. It focuses only on what is to be done, not how it is to be done. It screams functionality, and only whispers viability.