OER Knowledge CloudJournal Article20092009/01Smith, Marshall S.higher educationteaching materialsopen source softwarelibrariesInternetintellectual property rightsdisseminationeducational technology economicseducational technologydistance educationcurriculumcostscost analysiscomputer scienceinformation technologyengScience32389–93Spurred by the publication of Massachusetts Institute of Technology OpenCourseWare in 2002, the open educational resources (OER) movement, which has rapidly expanded and captured the imagination and energy of millions of creators and users throughout the world, now faces many opportunities and substantial challenges as it moves to become an integral part of the world's educational environment. The confluence of the Web and a spirit of sharing intellectual property have fueled a worldwide movement to make knowledge and education materials open to all for use. OER are content (courses, books, lesson plans, articles, etc.), tools (virtual laboratories, simulations, and games), and software that support learning and educational practice. OER are free on the Web, and most have licenses that allow copyright holders to retain ownership while providing specified rights for use in original and modified forms. At the least, OER have helped to level the distribution of knowledge across the world. A second promise of OER is to help transform educational practices. This article explores the history of and promises and challenges for OER.http://www.ncbi.nlm.nih.gov/pubmed/19119226http://www.ncbi.nlm.nih.gov/pubmed/19119226