If these books were used as data points and were associated as reasons to agree or disagree with a conclusion, we could use an algorithm to lend strength to an idea based on the books strength. Data is readily available from Amazon or E-bay or the New York Times best selling list of how well a book has sold.
So there would be three fields. One place where you submit the item that agrees or disagrees with the original idea. The second field would let you classify the object. Is it a book, a website, or simply alogical argument. The third field would be a place where the user explains why he thinks the book supports the conclusion that he/she has come to. Of course, people would be allowed to vote weather or not the book actually does support the side that the original user said that it would.
This is where the algorithm could get very sophisticated. Would you want to give more credibility to those who said they had actually read the book? Would you want to give even more credibility to those who had bought the book, as more proof that they actually read the book. Or how about people that used the website mediachest and could prove that they have the book, by the fact that they have let others use the book. What about people who wrote an essay on the book on the website. If Google was doing this, they could provide a place for users to write essays on books, similar to howAmazon lets users write essays. Perhaps they could not let people copy and paste essays into the form. It would only allow people to type their essays directly, to prevent stealing of essays. Perhaps people could vote on weather the book-essays were good or not similar to how Amazon lets users rate reviews, as to weather the review was "helpful" or not.
So, as an example, you could submit a best selling book as a reason to agree with an idea, and then right a thoroughly convincing explanation of why this book agrees with the idea, and an essay that proves that you understand the main points of the book.
If Google really wants to organize the worlds information, they must do this. We have plenty of books, we have plenty of content on the internet. We need ways of organizing this information into what it all means, and how all this information should affect us. The only good way information can affect us, is for it to help us make better decisions. In order for us to make better decisions, we must know all of the reasons to agree or disagree with a particular course of action. In order to do this, we should not start at ground zero, with only our own thoughts in our head. We should bring together all of thegreat thinkers from the ages from every corner of the planet, and organize all of their great thoughts, so that we can make the right decisions.
As you can see, this algorithm could be very simple, but it could also offer programmers hundreds of years of challenges to make it more sophisticated. I believe this is a strength of the idea, because it allows for continual improvement.