>>8
Well, first of all, the books are usually pretty worn-out, so it's not like they care.
It's basically about 'trusting society'. Believe it or not, not everyone is an ass. Some people don't mind sharing/giving away their stuff for the enjoyment of others.
The whole point is about sharing books that had some sort of impact on you and you want that book to change someone else's life as well.
>>9
I just looked it up, in my country it's just called 'bookcrossing'.