Check out A Mobile App Usability Tale… by email@example.com (Neil Perlin). Here is an excerpt:
It’s often taken for granted that mobile apps are so simple that they don’t need online documentation or help. That may be true but it’s risky to assume that that’s always true. Here’s a case where it wasn’t.
There’s a game called Fruit Ninja (thanks, Sandra, I think…), also…
The full article is available here.