Services like "library thing", if attached to reasonably-priced (whatever that means
) ebook-sales as a means to pay for the site, may be the best way to help people learn about new books in genres/writing styles they like. It leverages the social nature of people to want to share what they know/think with crowdsourcing that can produce far more accurate relationships between unknown/well-known/old/new books than any advertiser/publisher might.