Walking the Cow

Chalk it up to the long tail if you want, but niche tastes are starting to get their due on the iPhone. It started with ambient museum pieces…but now developers have worked their way around to something a little more fun.

Outsider troubadour Daniel Johnston just released his first iPhone app, a Mario-style platform-jumping game featuring characters from his artwork, music from his recordings and the same sense of addled optimism that  …