Usage drives sales, if you make it easy to buy (iBooks edition)

In the last few days I've started to play around a little with Apple's iBooks. As I'm reading on my iPhone4, at first I wasn't sure if I'd enjoy reading a book on a small screen. But after having read 2-3 previews of books, I realized it is a nice experience that that I think it can be a nice substitution to playing a game, checking Facebook or sending a text when I have 5-10 minutes in transit or am waiting for someone.

To try if I will enjoy reading a longer book on the small screen, I've bought Andrew Ross Sorkin's Too Big To Fail. I guess I'll know if the user experience holds for a long read in a week or two.

However, the actual book buying experience had a few interesting points.

* iBooks is a different application from the iTunes and App Store on the iPhone. It likely decreases initial adoption and usage, but I guess the tailor-made UI could be more effective in driving sales per user.
* iBooks has extensive previews of books (and a chunk of free public domain books), which is a good thing. The same way free applications in the App Store make it easy to spend time in that store, previews and public domain make it easy to spend time in iBooks.
* The combination of iTunes accounts with credit card information and people spending time exploring books will drive impulse buying. (I'd suggest that as good a technical platform the iPhone is, a big part of the general magic for music, apps and potentially books is the retail environment Apple has created with iTunes.)
* A big negative is that once I bought Too Big To Fail, I was told that the book was over 20 megabytes and could only be downloaded over WiFi. Not what I wanted to hear on the bus just having spent around £10. A nice solution would be partial downloads of chapters over 3G if Apple and the mobile operators don't want to push to much data over the 3G network.
* An observation is that while most apps cost one to a few pounds, books seem to hoover around £10. It will be interesting to see if book formats that allow for £1-5 price point develop.