The busy folks at MIT's Media Lab are at it again--this time it's an "emotional social intelligence prosthetic" for people with autism. The device consists of a miniature, glasses-mounted camera and face-analysis software. The system doesn't recognize a face so much as "calculate" the emotional state of its owner based on expression--furrowed brow, flared nostrils, pursed lips, rapidly-growing canines, etc. It will signal you when your interlocutor is becoming bored or otherwise irritated with the conversation.
I don't think the market is limited to those with autism--most of us could use this sort of device. I've often wished that the gentleman sitting next to me on a long flight were more emotionally intelligent than he is. (You'd think that long sighs, crossed eyes and the occasional lapse into a coma would be enough to quiet him down, and yet...) The really interesting possibilities here, of course, come from accurate lie detection. Presumably, analysis software sensitive enough to detect ennui will be able to detect the fine muscle movements that accompany deliberate falsehoods. Materials science could supply lenses that turn steadily pinker as the "deception index" rises (a new twist on seeing red