The idea of integrating users into the design and production process is a promising strategy for companies being forced to react to the growing individualization of demand. The use of e-business applications has been discussed as a approach for mass customization for over one decade. There is a huge amount of literature on manufacturing and information systems for mass customization. However, there has been little research looking at the role of the customer within the co-design process. Customers face new uncertainties and risks ("mass confusion") when acting as co-designers. We discuss possible risks evolving during the interaction between customers and suppliers. We propose solutions for the "mass confusion" problem, and we challenge the assumption made by most mass customization researchers that offering customized products requires an individual (one-to-one) relationship between the customer and the supplier. We envision a different way of addressing the probl...