I do research on the potential benefits and problems of sharing notes so I pay attention when a commercial organization thinks it can make a profit from this area. I find that students are quite willing to use notes I or a grad student generate, but I have not been successful in getting students to generate notes for each other. GradeGuru appears to think that the approach is to pay students. Potentially not a bad idea.
The immediate concern I would have is with copyright. What about the resources that instructors generate and make available to their students? There is a copyright sensitivity statement, but I am guessing this will work like so many other social sites. The site will not police beyond notification and will take down content someone complains about.
I am not sure what I think about this approach. In a way, Blackboard offers a safer environment by offering control at the institutional level, but this venture may generate more activity by sharing between institutions. The question then becomes what will Intro Psych notes taken at University XX offer to students taking Intro Psych from me. There were some Intro Psych notes available as sample content and the notes were quite complete.
I think the policies of this site could be improved. I know from my experience working on this topic that many instructors do not want to make their notes available. A common concern is attendance. While I do not think attendance is a serious issue, it seems disrespectful to ignore the wishes of course instructors. It would make sense to me to have instructors authorize use of their notes and to determine who can access notes. This is essentially the way services within Blackboard work. I think many instructors will see this as a valuable service and perhaps even participate in the use of this service (my research demonstrated that making outline notes available before class were particularly useful), but some will not and offering a way around their wishes seems disrespectful.
The guidelines offered by the site talk about appropriate things, but then back away without doing what can be done to assure ethical behavior. The site talks about copyright and suggests the use of institutionally affiliated email addresses, but then does not really make these guidelines requirements. This looks more like a concern for the bottom line than anything else.