Open Educational Resources (OER) are freely available and openly licensed content to be used for teaching, learning, and research.
Open Education "...is the simple and powerful idea that the world’s knowledge is a public good and that technology in general and the Web in particular provide an extraordinary opportunity for everyone to share, use, and reuse knowledge." Smith, M. Casserly, C. , “The Promise of Open Educational Resources. ,” Change: The Magazine of Higher Learning 38, no. 5 ( 2006 ): 8-17.
Types of OER Materials for Use:
Not OER, but can be used as class material under conditions: