From its website
OCW is a revolutionary approach to sharing educational resources. The site presents the core academic content–including lecture notes, syllabi, assignments and exams–from substantially all of MIT’s undergraduate and graduate curriculum freely and openly to support formal and informal learning around the world. Many of the site’s more than 1,900 courses also include rich media resources such as video lectures, simulations, and animations. OCW has inspired a worldwide movement that now includes hundreds of universities sharing materials from more than ten thousand courses.
Through OCW, educators improve courses and curricula, making their schools more effective; students find additional resources to help them succeed; and independent learners enrich their lives and use the content to tackle some of our world’s most difficult challenges, including sustainable development, climate change, and cancer eradication.