What are open licenses and what do they do?
Why do open licenses make a difference?
Most of what has been created in the 20th and 21st centuries – content to be found in libraries, archives, museums and on the Web – is still under copyright. Even if the authors' intention was different, unless they explicitly stated otherwise, their work falls under full copyright protection (its extent or remit sometimes differing from country to country). If we create and publish something new on the Internet today, without charges or restrictions such as DRM (Digital Rights Management), our work is available to read, watch, hear or use only for personal purposes. Our work is not available for others to copy, republish, update, remix, re-arrange, correct, create an alternative version of or add to Wikipedia. In order to do any of these things, one needs to obtain written permission, e.g., a specific license, from the author or copyright holder; and to do that one first needs to contact them. This might be viable for a commercial business or government body, but for the average user – teacher, student, blogger – the task can be next to impossible. Open licenses reverse that model and encourage authors and institutions to clearly state rights and permissions when publishing content. Choosing open licenses (such as the Creative Commons Attribution license and the Creative Commons Attribution-Share Alike license) is not unlike placing signs on a public road. Routes can be chosen as long as signs – like those pertaining to attribution – are obeyed. This makes reuse and cooperation easy and quick, eliminating the need to negotiate and reducing legal uncertainty. Using licenses compatible with the Open Definition ensures that users have clear rights, that the barrier to reuse is lowered, and that educational resources proliferate. Just like Wikipedia or digitized paintings in the Public Domain, it opens up new, progressive ideas that would have been unimaginable a few years ago.
Want to know more? http://opendefinition.org/
This answer is from the publication Open Educational Resources Mythbusting by Karolina Grodecka and Kamil Silwowski, available under Creative Commons Attribution 4.0 International license (CC-BY).