Book Recommendation System

A user I host has sent me the following request:

I want a place to keep track of books I want to read, an online space to note what titles I put on my mental “I must read this…” checklist. I would have to be able to maintain a list of books people have recommended to me, as well as a way to recommend books to others. It must have a way to comment on books after reading them – to write my own personal book jacket blurbs. I want to see published reviews of these and similar books, and my friends’ mini-reviews. I also want the option to make certain ratings available just for me, and not my friends – cause not everyone needs to know how far along I am in the Animorph series. (I bought them for my brother, anyway!)

I want Netflix’s movie rating and recommendation system, with a few modifications, but for books. I want it to be beautiful, to be graphically interesting and intuitively accessible. I want “two cents” reviews and a queue, with email reminders when my favorite authors release new books so I don’t miss anything.

Does something like this already exist? Does anyone have any suggestions on where to start?