Meta-design is an emerging conceptual framework aimed at defining and creating socio-technical environments as living entities. It extends existing design methodologies focused on the development of a system at design time by allowing users to become co-designers at use time. Meta-design is grounded in the basic assumption that future uses and problems cannot be completely anticipated at design time, when a system is developed. Users, at use time, will discover mismatches between their needs and the support that an existing system can provide for them. Meta-design extends boundaries by supporting users as active contributors who can transcend the functionality and content of existing systems. By facilitating these possibilities, control is distributed among all stakeholders in the design process. This paper characterizes different design methodologies and identifies the unique challenges and opportunities for meta-design. It illustrates this approach with two examples: (a) Web2Gether (...