I recently checked this site in response to someone who was trying to start a discussion here by insulting teachers.
Supposedly, teachers are not being quick enough to embrace something called a "open content curriculum" which appears to be the buzz words for something so new, no one can define it as yet. The discussion referred me to the website http://creativecommons.org/
which I have visited several times. Seems the site is a so-called "non-profit" that solicits donations without having any project of goal that the donations contribute to. They profide a "Free" license to do what you can do with your work with or without the license. It just tells people how they can use your resources. Since you don't register for the license, you would have no more or less legal standing than if you merely stated on the site how you are willing to share your work. Under the heading of "opportunities", they are offering no jobs, bur seeking volunteers. The staff appears to be made up mostly of young people, some not out of college yet, who are volunteering. The annual audit shows contributions received in the millions with nothing going out but small amounts in expenses, which obviously are not spent on a payroll. The annual statement indicates that the company owns millions in "assets". The link to show examples of their "users" leads to a choice of search engines which produce the usual output for what you put in. There is a disclaimer saying that you can't know if anyone has their license, unless you communicate with the owner of the site.
In short, unless someone else knows anything positive about this site, I would suggest that those who are making web content steer clear of it. Certainly, don't "donate" any money to them.
And, please, teachers, don't be offput from questioning possible scams and unsupported "facts" by being told you are "unprofessional".
Being a professional does not mean being a patsy for those with ulterior motives.