BASICALLY, you take a book you own and you register it on this site. You then get a BCID (book crossing ID), you label your book with the BCID and any other distinguishing marks you wish to place in/on your book, and then you release it. Either by leaving it somewhere someone will find it or giving it to someone. Once a book with a BCID is found you go to the site and type in the ID and the person who released it gets an email and TA-DA! The magic of some random person finding your book. And who knows how far your book may travel!
If this isn’t the coolest thing you’ve seen in a while, you’re lying. We should all do this and see who gets our books. I’m in.