If you’re a Kindle user, you know that you can manage your Kindle library on your Amazon account page. There’s a link that says Manage Your Kindle:
This takes you to a page where you can see your content and your devices, and alter some settings related to your Kindle account page. From the Your Content section, you can choose to deliver a book to one of your devices, but you can just as easily download it from the device itself. You can also delete the book, clear the furthest page read, and more.
But there’s a secret, “hidden” Kindle page which is much more useful. Go to http://kindle.amazon.com/, sign in, and see how much more information you get.
Click Your Books, and see all your books, what your reading status is for each one (whether you’re currently reading, finished, etc.), rate books, and set whether you want your notes to be public.
One thing available from this page that you cannot access any other way is Your Highlights. This lists all the passages you’ve highlighted in all your books, and you can copy them. Since there’s no way to copy text from a Kindle book, this is a good way to get bits of text if you need them for, say, a report or article.
You can also follow people from this page, but I’ve never really felt this to be useful. Perhaps you want to follow famous authors and read their notes and highlights, or just see what your friends are reading; as long is this information is made public.
While some of the information on this page is the same as that on the Manage Your Kindle page, the main attraction here is highlights. As far as I know, this is the only way to access them in copyable form. Check out this page; you might find it useful.