[throwaway4aday]

This was partially solved by the internet and Google Books although there's still a lot of room for improvement. We really need to get all of the books in the world digitized and behind an API that allows anyone to access all of the content with some sane pricing scheme rather than charging per book. I doubt this will ever happen so the best we can hope for are the various efforts to pirate as many books as possible and make them available for download. It would be a dream to have a really good search over all of the written works of mankind though.

[skydhash]

Yes, but some books require extensive effort to write while others are produced factory like. How do we take that in account?

[throwaway4aday]

It shouldn't be, the effort with which something is produced has zero weight when judging its value. For books they should be rated based on their purpose. Non-fiction should be rated along dimensions of accuracy, new information, utility, clarity and absence of errors. Fiction should be rated on how entertaining and inventive it is among other things. If you want to subdivide further I'm sure you could come up with other meaningful criteria.