^ this. Write reviews for popular courses and you attract attention. Write reviews for unpopular courses and you get few thumbs. So far, I've written 84 reviews:
10 reviews account for 33% of my total responses, all of those are for big name courses that are popular inside and outside the state they are in.
I also have 21 reviews that account for than 9% of my responses, because no one really seems to care about those courses.