I’ve recently discovered another online Kindle book lending club called Lendle. It’s much better than the previously mentioned Book Lending because it has much more users and most of the books are already lendable so no waiting time.
After signing up (using twitter, facebook or registering), the user must mark at least one book which he/she owns, in order to be able to start borrowing books. I find this a bit stupid in case of non-US customers, because we cannot lend books. Nevertheless, as soon as I marked one book, I was able to place my borrow request. Note that a user can add up to 3 borrow requests on Lendle, in comparison to Book Lending, where a user can place infinite borrow requests but to a limit of 5 per day.