—This paper presents the open learning object repository and collaborative authoring platform LeMill (http://lemill.net), which has over 7,500 members and over 8,500 reusable learning resources (situation in October 30th, 2009), all created by the community members. The design of LeMill has tackled numerous challenges that hinder the authoring and sharing of educational resources by communities of teachers. This paper describes the research-based design process that was used to solve these challenges. The information architecture of LeMill scaffolds authors toward collaboration and sharing. The licensing scheme encourages reusing and remixing of educational content. In order to make LeMill easy to learn and use we have avoided technical terminology and complicated metadata forms in the user interface. As an open community we have also tackled multicultural and multilingual issues. In this paper, we present the information architecture and design of LeMill, including the technical sol...