Relevant to recent discussions here, oyster is a service that let’s you subscribe for $10 a month and it works like a book library. Get as many books as you like. It is like last.fm or spotify for books, haven’t looked at it yet but the design experience looks good. The article on wired is worth a read.
Things to notice. It is not selling books, it is selling a service. It relies on mobile media, it is not selling ‘things’, it is subscription based which means an ongoing revenue model.