This chapter introduces the notions of metarule of law and socio-legal ecosystems to both foster and regulate linked democracy. It explores the way of stimulating innovative regulations and building a regulatory quadrant for the rule of law. The chapter summarises briefly (i) the notions of responsive, better and smart regulation; (ii) requirements for legal interchange languages (legal interoperability); (iii) and cognitive ecology approaches. It shows how the protections of the substantive rule of law can be embedded into the semantic languages of the web of data and reflects on the conditions that make possible their enactment and implementation as a socio-legal ecosystem. The chapter suggests in the end a reusable multi-levelled meta-model and four notions of legal validity: positive, composite, formal, and ecological. Keywords Web of data Á Socio-legal ecosystem Á Rule of law Á Metarule of law Á Semantic languages Á Governance Á Linked democracy Á Semantic web regulatory models Á Regulatory quadrant Á Legal validity 5.1 Introduction: The Rule of Law in a New Brave World We will expand in this chapter some ways of implementing linked democracy on legal and political bases. Linked democracy is not only a theoretical approach incorporating open linked data to theories of democracy. It consists of practices and the real behaviour of people exercising their political rights on everyday bases. Thus, it also possesses a personal and cultural dimension that should be valued and protected. Law is an obvious element. Behaviour on the web should be 'fair' and 'legal'. What does it mean? Different states have different jurisdictions, and despite the international trends of the global market, law has been, and still is, dependent on national states. How could we incorporate regulatory forms of empowering people on the web? How could algorithmic governance, data analytics, and semantics be used to foster the principles of linked democracy that we have just presented at the end of Chap. 4?