I’m intrigued by this. Not least because 5,000 paperbacks in 7 months is 23 books a day. Impressive stuff, though I wonder if ut makes any money:
Politics and Prose has produced almost 5,000 paperback books — some in as little as five minutes — since receiving the book machine nicknamed “Opus” last November. Leggett said about 90 percent of the books printed on the machine are self-published works by local authors.
The others are out-of-print editions, millions of titles available in the public domain like Google Books, and digital formats licensed out through major publishers including Harper Collins.
Alfred Morgan Jr. was able to get a copy of his father’s out-of-print 1923 aviation guide, “How to Build a 20-foot Bi-Plane Glider,” printed on the machine for $8. The volume was on Google Books.
via Independent bookstores embrace digital publishing with ‘espresso’ book machine – The Washington Post.
Eoin Purcell's Blog 
I have long believed that this is the future of many bookshop sales, if not of bookshops themselves – with millions of titles available, no bookshop can hope to hold all in stock – yet, since they exist digitally, they can be acquired for a reader and printed locally to meet demand. Makes sense for university libraries, independent bookshops or specialist bookshops. They’ll be like Chinese take-aways: just a counter where you order ISBN 978XXXXXXXX (instead #47 and chips) and pay!
Have you see Paperight? Tag line: ‘Turn your copyshop into a bookshop’ I think it could be huge! http://paperight.com/
How many people go to the trouble of ordering a book they just heard or read about? Most people I know love the experience of browing in a bookstore, picking up a paperback or hardback at whim and making a decision based on emotion. It helps if the book is prominently displayed but I also like looking on the shelves and picking up some gem at random.
Quite a few do, it’s a nice earner for some bookstores.