|Answer added on 5-9-2011: Shelfari|
Shelfari is a social cataloging website for books.
Shelfari users build virtual bookshelves of the titles they own or have read, and can rate, review, tag, and discuss their books.
Shelfari was launched on October 11, 2006.
In February 2007, Amazon.com invested $1 million in Shelfari, and moved to acquire it a year later in August 2008.