In a recent article, Gena Phillibert-Ortega introduced me to a blog called Forgotten Bookmarks. Michael Popek is a bookseller and runs across all sorts of items left between the pages of books. He’s found everything from photos to recipes to grocery lists to letters, and just about everything in between. He blogs about his findings at Forgotten Bookmarks. Be sure to check it out!
Michael also published a book, Forgotten Bookmarks: A Bookseller's Collection of Odd Things Lost Between the Pages, that has several bookmarks that he hasn’t blogged about.