I've just started using RTM to keep track of books I've spotted or heard about from colleagues, and want to read at a later date. I started with just one list called "Books", but now I've added "sub-lists" based on *why* I'd want to read the book - professional development, entertainment/enjoyment, or to seem smart to my bookish friends (I often just read the Sparknotes for these). When I'm done, I "complete" the task, and sometimes add notes on what it was I liked or disliked about the books so I can pass along my ideas about the books.