This has the potential to be huge, especially since it's the brainchild of Google. One thing I noticed is that they didn't showcase object recognition of any type in the promo video. When I heard they were testing these glasses, Google Goggles is the first thing that came to mind. It would be really useful to auto-search objects by simply looking at them and issuing a command. I'm sure it's on their roadmap, if it's…
Tom Furness developed similar devices decades ago: Once out of the military lab, this was a key project of the Human Interface Technology Lab at UW in Seattle in the early 1990's.
Updating for smaller chips and components contributes to the current form-factor which includes the front-facing camera not present in the earliest versions.
The upside of course is that this might finally get some traction with Google's budget and efforts.