I can't see any legit use for an average Joe in Glass apart from having both of your hands free while recording your kittens/puppies for the internet.
The whole concept of Glass reeks of spying/stalking (cheating in school comes to mind as well) and is surely going to make people around you very uncomfortable. It makes absolutely no sense whatsoever for anyone to know the name and whatever other information it might provide of every passer-by on the street.
What makes all of this even worse is that you could essentially be tracked down hour per hour by different Glass users without neither you nor them knowing, providing Google with nice log files on your locations for sale to the highest bidder.
This product just plain out stinks of dung to me. I hope it gets banned by the Court of Human Rights.
The problem is that like every electronic product it can be reprogrammed. So even if google respects every privacy law in the world, it's a breeze to trasform it into a spy machine. Just think about what spyware are able to do into our pc, and imagine to install one into the glasses....
I'm less concerned about what Google plans to do with the data. Than say the NSA tapping into video feeds around the world for an unparalleled ability to spy or the UK. All in the name of public safety or stopping terrorism. While in reality it is used so the government can control it's populace or at least have the infrastructure in place to do so if it takes a bad turn, which can happen very quickly.
I think that a product like this is in our future weather you like it or not. I love it. You all think you have so many secrets, that seeing your face and having who you are pop up on the Glass users interface is some big erosion of your privacy. Wear a paper bag, probably couldn't hurt anyhow.