Much, much more in this post to read, but the graph that grabbed me was this:
Placed in the context of publishing, this makes Google a critically interesting entrant in the tablet wars. Google has not heretofore made a big splash in digital book sales, although it has long been deeply engaged in publishing for years through its Google Book Search program, which has seen several iterations and re-brandings, not to mention a few “minor” legal skirmishes. Indeed, Google rather ingloriously pulled out of its partnership with independent book stores recently, leaving a market opening that others, like Zola Books, are racing to fill. Yet every indication suggests that books are integral to the Google Play release; as The Verge’s Tim Carmody notes, all of the Nexus 7′s most prominent competitors are reading tablets.
Eoin Purcell's Blog 