One of the progression of user-centric design methodologies is to engage the end-users in design decisions rather than just using them as a feedback mechanism. This is supported by many common tools (e.g. Uservoice or GetSatisfaction) that allow users to provide suggestions/ideas and then for them to be ranked based on popularity (as voted by the users) or other metrics (importance, amount of time or effort required). Once the users provide enough details/requirements/specifications for the product/service to be developed, the company can then build the product with the view that it should basically almost meet the exact user requirements.
However, unlike decisions made based business, technical or even user requirements that are initially based on some degree of research and analysis of users, if the product/service design is based directly on something that the users collectively come up with then how would you have to evaluate user satisfaction to take into account that the users came up with the design? Is this even something that makes sense to do since the users are responsible for the outcome and the company is creating a product/service as a service