The CK-12 Foundation has decided to update its content licensing type from Creative Commons By-Attribution-Share-Alike to Creative Commons By-Attribution-Non-Commercial-Share-Alike .

CK-12 Foundation is a non-profit organization with a mission to reduce the cost of textbook materials for the K-12 market both in the U.S. and worldwide. Using an open-content, web-based collaborative model termed the "FlexBook," CK-12 intends to pioneer the generation and distribution of high quality educational content that will serve both as core text as well as provide an adaptive environment for learning.
 
Donors had been asking CK-12 to rethink its license because they were not comfortable with the fact that anyone could use their content for commercial purposes. Additionally some of its content users had requested that CK-12 make its license interoperable with university initiatives like MIT’s Open Courseware.  

After evaluating how well the new license works for other Open Educational Resources (OER) consortia like MIT’s Open Courseware and Carnegie Mellon University’s Open Learning Initiative, CK-12 decided adopting this approach was better for its donors and content users.  The organization will maintain its open and sharing spirit while protecting the hard work of its donors.  
 
Users may continue to share and modify materials as they see fit, however, they should contact CK-12 if they wish to commercialize content.