Bookhunch is meant to be a social, crowdsourced review site for new and unpublished literature. Readers are able to leave their mark on the in-site book display to interact with other users and earn points for additional access privileges. There are very few books available on the site right now, but if they gain access to the exclusive pre-pub content they’re after, a big user community should follow.
The concept seems very cool and it’s currently invitation-only (mine a few days after I requested it) so they’ve built a very engaged user-base that seems to reflect the ultimate purpose of the site. Users leave insightful comments against an in-site view of the book content. Most of their books are public domain, but as the site develops it should be easier for users to find interesting content.