The terms "open content" and "open educational resources" describe any copyrightable work (traditionally excluding software, which is described by other terms like "open source") that is licensed in a manner that provides users with free and perpetual permission to engage in the 5R activities:
While a free and perpetual grant of the 5R permissions by means of an "open license" qualifies a creative work to be described as open content or an open educational resource, many open licenses place requirements (e.g., mandating that derivative works adopt a certain license) and restrictions (e.g., prohibiting "commercial" use) on users as a condition of the grant of the 5R permissions. The inclusion of requirements and restrictions in open licenses make open content and OER less open than they would be without these requirements and restrictions.
There is disagreement in the community about which requirements and restrictions should never, sometimes, or always be included in open licenses. For example, Creative Commons, the most important provider of open licenses for content, offers licenses that prohibit commercial use. While some in the community believe there are important use cases where the noncommercial restriction is desirable, many in the community strongly criticize and eschew the noncommercial restriction.
As another example, Wikipedia, one of the most important collections of open content, requires all derivative works to adopt a specific license - CC BY SA. MIT OpenCourseWare, another of the most important collections of open content, requires all derivative works to adopt a specific license - CC BY NC SA. While each site clearly believes that the ShareAlike requirement promotes its particular use case, the requirement makes the sites' content incompatible in an esoteric way that intelligent, well-meaning people can easily miss.
Generally speaking, while the choice by open content publishers to use licenses that include requirements and restrictions can optimize their ability to accomplish their own local goals, the choice typically harms the global goals of the broader open content community.
Should you choose to exercise any of the 5R permissions granted under the Creative Commons Attribution 4.0 license, attribute as follows:
For redistributing verbatim copies of this page: This material was created by David Wiley and published freely under a Creative Commons Attribution 4.0 license at http://opencontent.org/definition/.
For redistributing revised or remixed versions of this page: This material is based on original writing by David Wiley, which was published freely under a Creative Commons Attribution 4.0 license at http://opencontent.org/definition/.