For the final exam, I was asked to critique crystalinks.com. This was a website with plenty of copyrighted material from the author, crystal. The reason this information is so valuable is because it's her intellectual property that she feels should be protected. This copyright will protect others from reusing or stealing her work.
There is the fair use act that is the alternative to asking permission of copyrighted work. This is constituted in cases criticism, comments, news reporting, and teaching.
I examined the website, teachers pay teachers, in order to determine the ethics and legality of the site. Based on what I observed, this seems to be a pretty ethical place to exchange and by teaching materials. The teachers will sell the website owners original material. The owners now sell the material to education institutions or teachers. The owners of the website have to be extremely careful not to obtain material that isn't original because of copyright infringement.