Amazon has a new feature for Kindle users (you need to sign in). You can keep tabs on the books you are reading, have read, or stopped reading, and the notes you made on them. You can choose to make this information public.
Of course, I rushed to see if readers had highlighted anything on my books. With Remix, proudly ranking 4395th in books with Public Notes, oddly it's the first lines and my website address. With Replica, I was delighted to find this note on the thoughts of my hero, Nick Cavanagh: