James Grimmelmann, Three Theories of Copyright in Ratings
Short and very good:
If ratings are facts, then they are discovered; the rater’s job is to investigate the world to learn the true facts about the subject. If ratings are opinions, then they are created; the rater’s job is to produce a personal evaluation of the subject. If ratings are self-fulfilling prophecies, then they are imposed; the rater’s job is to provide a vision so compelling it will be universally accepted. The telos of a rating-as-fact is truth; the telos of a rating-as-opinion is authenticity; the telos of a rating-as-prophecy is power.