Print on Demand Bookstores

I came across this interesting blog post about the perfect bookstore and it got me thinking about what impact Print On Demand might have on future libraries? Surely, one of the big points of difference between libraries and bookstores, apart from price of course, is access to the long tail - out of print and hard to find books.

If (when?) Print On Demand takes off will it do for books what iTunes did for CDs and music publishing - fundamentally change the game? Or will we all be reading ebooks by then and printing itself will be thought of as an odd idea, in the same way that digital cameras have changed the demand for printed photos?