So much of the mobile experience is context and location specific. App use tends to be more immediate, reactive and transient, prompted by something that happens in the users' environment rather than by their work schedule.
Traditional lab methods really don't work too well to capture these behaviors. From a physical perspective there is seldom a video-out port to capture screen images, and there is no easy way to capture gestures or button presses. From a behavioral perspective, it's often hard to "set the scene" for your app's use when your user is sitting inside a sterile office room.
So how do we cheaply and quickly gather feedback on the mobile apps that we develop? What techniques can we use to balance ecological validity with solid data collection?