Some great work here on how publishing on the iPad is evolving (in the US at least). There are 46,000 (paid and free) books available through the iBooks app, O'Reilly tell us, a third of which are fiction titles. The founding five publishers dominate the output with Penguin top dog with 24% of all iBooks. The piece also has a link to the median price paid for these digital books. In most categories the price is above $10, but in some (romance, fantasy and erotica) well below. Who'd have thought it.