The report describes a triple threat of low discoverability, low memorability and accidental activation. This means that users often don't know what functions their apps have, they don't remember how to use each app because each app works so differently, and they will mistakenly use features through accidental gestures.
It came to the overall conclusion that the iPad user interface shouldn't be a scaled-up iPhone UI.
The study found that the chief difference between the iPad and iPhone in terms of usability was that the tab bar at the bottom of the screen works much worse on iPad than on iPhone. The report explains that on the small phone, users are likely to notice the muted icons at the bottom of the screen, even if their attention is on content in the middle of the screen. But the iPad's much bigger screen means that users are typically directing their gaze far from the tab bar and they ignore (and forget) those buttons.
Also, after testing many websites it was concluded that the iPad was much better at web browsing than the iPhone, so there should be some sort of enhancement for the iPad. While websites "work reasonably well" and are "beautiful" on the iPad, it was also found that "users don't know where to click."
Continue to the next page to find what usability features the focus group wanted from their iPad.
* Add dimensionality and better define individual interactive areas to increase discoverability through perceived affordances of what users can do where.
* To achieve these interactive benefits, loosen up the etched-glass aesthetic. Going beyond the flatland of iPad's first-generation apps might create slightly less attractive screens, but designers can retain most of the good looks by making the GUI cues more subtle than the heavy-handed visuals used in the Macintosh-to-Windows-7 progression of GUI styles.
* Abandon the hope of value-add through weirdness. Better to use consistent interaction techniques that empower users to focus on your content instead of wondering how to get it.
* Support standard navigation, including a Back feature, search, clickable headlines, and a homepage for most apps.
The report concludes with a hypothesis that seems to be accurate, at least for now.
"Maybe people will begin to use the desktop Web for more goal-driven activities, such as researching new issues or performing directed tasks like shopping and managing their investments. And they might use the iPad for more leisurely activities, such as keeping up with the news (whether "real" news or social network updates) and consuming entertainment-oriented content. We don't know yet.
"The answer to this question will determine how far iPad UIs have to move from their current wacky style."
The full report was completed by the Nielsen Norman Group and can be found here.