Initiatives aiming at the preservation of the public domain constitute an important element of the WIPO Development Agenda. With the WIPO-commissioned Study on Misappropriation of Signs, the international debate on how to preserve a rich and accessible public domain has reached trademark law. This debate raises fundamental questions about the relationship between the rationales of trademark protection and the need to safeguard the public domain. How should the public domain be defined in relation to the trademark system? Which preservation tools are available under trademark law? What lessons can be learned from the way in which these tools are used in different countries? How can these experiences be translated into best practices that can serve as guidelines for countries seeking to support a robust public domain?
Against this background, the present article explores the notion of the public domain with regard to trademark law. It will be argued that a broad conception of the public domain is appropriate — a conception which, besides signs unencumbered by trademark rights, includes user freedoms resulting from a limited scope of protection. By surveying the universal rules laid down in international treaties, four categories of preservation tools can be distinguished on this basis: a general bar to trademark protection, the exclusion based on a sign’s lack of distinctiveness, inherent limits of exclusive rights and the adoption of exceptions. After this conceptual clarification, the use of the identified preservation mechanisms in EU trademark law will be analyzed to illustrate the role that the different tools can play in safeguarding the public domain. The EU is an interesting example because it reflects a regional rather than national approach that includes countries from both the continental-European and the Anglo-American tradition. The analysis gives rise to the question whether the EU approach can serve as a model for other regions.