Internet-based platforms present new opportunities for theory and design in Information Systems. The social implications of technological change have always been important, but new platforms, with their changes in negotiated social order and contending opportunities for freedom and control, require an explicitly critical perspective. If democratization is to be a feature of platforms, we need adequate distinctions for the design of these social/organizational spaces. Critical theory provides such a framework, and a way to sort out the disconnects between intent and implementation. Habermas’s concepts of the system, public sphere, and lifeworld provide a social philosophy that can directly influence IS research and design. Using health care trends that bring patient lifeworld and hospital system into closer contact, we illustrate a gap in conventions that arises, and recommend this gap be formatted as a public sphere.