There are some very important differences that make it incomparable: * libraries have a limited amount of copies. So the amount of non-paying readers is not in

There are some very important differences that make it incomparable: * libraries have a limited amount of copies. So the amount of non-paying readers is not indefinate * the readers have to return the copies of books or DVDs they have rented These inconveniences makes buying a copy for personal use much more attractive for the consumer.