Things I like: - the sign up form was really easy, which is good - I like the star rating / comment combination, as it allows people to give details - the ability to rank the difficulty of a course is nice (I'm assuming you have plans to somehow display this data once you have enough of it seeded) - the ability to filter courses by tag is good (though who is deciding the tags?)

Things that could be improved: - the Sign In With Twitter didn't work for me, I got an error - I'd like to see a more detailed rating system (like rating the course on several criteria - 3 stars for material, 5 stars for instructor responsiveness, etc) - I think the ability to up-vote or down-vote reviews would be nice - The comment section should be more helpful in writing a review (suggest things the reviewer should talk about)

The value in this type of system is around the quality of the feedback. To that end, you need to make it a priority to get quality reviews from users. Having suggestions of what the user should write about, weighting reviews by up-votes, etc. are just ways to increase the quality of the reviews you receive. Things like "Nice course." aren't going to be helpful to anyone.