Exactly What Hardware Lays Behind Amazon's eBook Sales Surge?

ZDNet's Larry Dignan asks whether Amazon's eBook sales explosion has been occasioned by the spread of Kindle hardware, or the popularity of the iPad and the Kindle app for iPad:

Amazon’s price cut was a month ago and definitely helped accelerate things. However, the Kindle to hardcover book ratio was already at an inflection point three months ago. What happened a little more than three months ago? The iPad launched. On April 3, the iPad debuted and sold 300,000 devices. Eighty days later Apple sold, three million iPads.

Meanwhile, Amazon was all set with its snazzy Kindle iPad app. ...

The most plausible reason for the e-book jump is the iPad. Jefferies analyst Youseff Squali connects the iPad dots:

We believe that Kindle’s e-book sales are benefiting from the launch of the iPad, since the Kindle e-book store offers a broad (and probably the richest) selection, with over 630K titles, which iPad owners can easily chose from.

Our current estimates for 2H10/FY11 could also prove conservative as we assume only 10% Y/Y growth in Kindle device sales with no contribution to e-book sales from the iPad. A more probable scenario, based on a higher unit sales of Kindle and e-books, yields an additional ~$100M and $200M upside to our revenue estimates for FY10 and FY11.

Squali reckons that there will be roughly 4.62 million Kindles in circulation by the end of the year. Given that figure, it’s likely that the iPad led to Amazon’s e-book inflection rate. ...

Whatever the hardware, these eBook sales figures are terrific news for Amazon. In my opinion Bezos is far more interested in owning the ecosystem within which people read than he is in owning the hardware. Kindle on iPad. Kindle on Android devices. Whatever. Bezos wants to sell content. And he's right.