David Smith pointed to this article about innovation at P&G. I think it smacks a little too much of the corporate Kool Aid; I'm just naturally wary of claims about "transformation", especially of human beings. Still, this quote about their experience of co-creating with customers resonates well with me:

Participants get scared using such rough prototypes to elicit consumer feedback at the beginning, but they are won over when they see the benefits of co-creation," says Kotchka. "We have found that the more finished a prototype is, the less feedback people will give you. When you give prospective users something half-finished, they think you don't know the answer. They know you need their help—and really open up.