The redundancy is unintentional...need to fix. If you sign up, you get to add books to your 'Reading List' (link under book show page image), enter giveaways and receive a newsletter with top rated books. We plan on adding more features...
Also, Amazon links would be great. You got me interested in a few books, and I'm ready to buy them. The site should definitely get an affiliate fee for that.
Sounds great; just signed up. You should advertise the benefits on your Sign Up page (and/or homepage).