Or, this could lead to the birth of a decentralised web-of-trust review and recommendation system. Imagine if something like this works: When a person reads a book, he rates it according to his taste. He would also rate how much he "trusts" the opinion of any of his peers. Then, for any book, he could ask the question "How good do my peers think this book is?" or "How good does the faculty of University of Manchester School of Computer Science collectively think this book is?" This then propagates the ratings of this group, and the ratings of the people they "trust", to come up with an answer. The amount of trust can act as some sort of a coefficient at each step.

Now, instead of saying "a group of well-read professionals, picked and chosen by Random House, thought this books was good enough," you can say "a group of people, whom I trust to be well-read professionals, or to have good taste, or to be accurate, or to be knowledgeable in their field, thought this books was good."

The technology is there, and frankly I won't be surprised if someone already wrote something like this.

BTW, this isn't limited to books. You can substitute "book" with academic paper (and you get peer review!), films, music, or pretty much anything provided by a social-web recommendation service,