Quotation books are a major player for ready-reference work. Everyone is always looking for a good quote to use for toasts, speeches, or an article starter. A del.icio.us clone for quotes was bound to arrive sooner or later, so say hello to Big Cite. Why is this so great (if it catches on)? Just like using del.icio.us as a collective wisdom and trust factors for links, Big Cite will do the same for quotations. If as many people as possible contribute to it, it can become larger than any reference book. Plus, it gets indexed by the people adding the quotes. Add this one to your ready reference links for sure.
Plus, it has a built in concordance (kinda).