“What is BookCrossing, you ask? […] the books our members leave in the wild are free… but it’s the act of freeing books that points to the heart of BookCrossing. Book trading has never been more exciting, more serendipitous, than with BookCrossing. Our goal, simply, is to make the whole world a library. BookCrossing is a book exchange of infinite proportion, the first and only of its kind. […] It’s also a fascinating exercise in fate, karma, or whatever you want to call the chain of events that can occur between two or more lives and one piece of literature.”
It’s like Where’s George? except with books… and you give them away.