I think anything that you believe would be a valuable resource to any community should be shared: whether it be something as small as how to bake cookies to something like lectures and a way to better understand a subject. If you have a talent/resource, share it. I think it would be great for students to share notes or ideas on specific projects.
I think a problem with OER would be the attribution. Some people might think that with a resource like this where everything is out in the open and ready to use and remix, the need to attribute the original to the creator isn't first priority. Why attribute it when you have your information naked and for the world to use as it may? In a class, you have teachers reminding you constantly, cite your work, include source information! But with OER, it might be hard to regulate that.