When I first started reading about this story, I thought it was another of Google's April Fools Day jokes. Does anyone remember Georgi LaForge, on Star Trek? These look a cross between those glasses and the technology used in The Minority Report.
Although I have to hand it to Google for usually being out front in the world of technology (their numerous failed attempts to recreate the social network notwithstanding), I'm afraid this one is just plain dangerous. Even more dangerous than robot-driven cars.
I know I would find having "helpful" information popping up in front of me very distracting. And as for putting "helpful" information in front of me at the right time, it's not as if the glasses are actually going to know what I'm THINKING (I hope). I may be looking in the direction of a woman who has a Gucci handbag (which may be advertised, conveniently on Google), but I may actually be focused on a set of restroom signs, to figure out which one is the girls room (and please, please, Google - don't even TRY to help me with that).
But one really great thing that is likely to come out of this is that the technology is likely to be used in making our mobile devices intuitive in a way that we've never seen before. Better assistance with street-level directions, and special offers for restaurants and retail stores I'm actually walking into would, in fact be appreciated. We're already getting there with applications like Google Maps, and Foursquare.
If Google really wants to make bring this technology into the Star-Trek age, I hope they ditch the eyewear, and focus on developing a great projection screen for their Androids.