“BookSwim aims to be the ‘Netflix of books.’ Since 1998, Netflix has become the king of online DVD services by renting batches of DVDs via the mail for a fixed monthly fee, and letting subscribers keep the movies as long as they like. That’s how BookSwim is meant to work. For $15 to $20 per month, the company will send your top five book choices. Return three books in a prepaid envelope, and your next three choices will be mailed to you.”