Social software and Web 2.0 provides new opportunities for participation and collaborative knowledge construction in peer support and self-care to live well despite transient or permanent health problems. Opportunities include many to many interactions to share and accumulate knowledge and experiences from several perspectives. We are conducting a study to create a collaborative environment for peer support and knowledge construction related to a rare condition. The study draws from participatory design and agile approach to development; extensively using design workshops and iterative prototyping. Several workshops led to systematize perspectives of different participant groups, and provided feedback about functionalities illustrated in different mock-ups and prototypes. Here we report experiences, and focus on feedback from participants leading to special considerations in design of the web-based environment.