In the software world, the concepts of “free software” and “open source” have defined meanings. With the development of licenses governing content, the terms “free content” and “open content” have become commonly used but without clear definitions. An initiative has been started by Erik Möller and Benjamin Mako Hill to define what “free content” or “free expression” (the very word content is itself up for debate in this process) means and which licenses satisfy this definition. There is also a contest to devise a logo that can be attached to works or licenses which are free under the new definition.
The full announcement for this undertaking is here.