My assumption is that a reader who stops at a review has not yet got hold of the book or seen the movie. So naturally the first thing he would want to know is, "Is the book/movie any good - is it worth my money?"
Which is what I look for in reviews, and which is why my reviews are the way they are. I sometimes do not even speak about the theme. My reviews only speak about what I felt about it. What I dis/liked about it. What to look out for in the movie. Probably that is not what others would want...
However, one of my friends who read my review of Slumdog Millionaire, said that it helped her set a base, otherwise she would perhaps have not sat through the movie at all.
Check out my Book Reviews and Movie Reviews here.
Let me know what you expect when you come across a review?