Ben Lorica’s excellent post at O’Reilly Radar (Waiting for the Billionth Download) is full of details about iPhone apps. A bit overshadowed is the growth in the Books category. I’ve done some clipping and rearranging on one of Lorica’s charts to bring this out — Note that the Rate-of-Change for books in the last 3 months is at least double the rate for all other categories except Travel.
Another notable growth category shown here is Medical — Though its share of all apps is still small, it’s the third fastest-growing app, behind books and travel.
Here’s Lorica’s text on books:
Measured in terms of number of unique apps Books remains the fastest-growing category: during the week ending 4/12/2009, 11% of the apps in the U.S. store were in the Books category. Books has surpassed the Utilities category and may soon overtake the Entertainment category. Over the past week, Kindle for iPhone was the top app in the Books category.
Here’s the whole chart from Lorica’s article, with all 20 categories of apps: