I've stayed out of this debate so far for various reasons, but there is a specific privacy issue with Glass that I haven't noticed anyone else raising yet.

It is inevitable that Google Glass will have real time facial recognition, whether Google wants them to or not (http://www.wired.co.uk/news/archive/2013-06/11/google-glass-...). Or, that a similar product offering that capability hits the market once Glass becomes popular enough.

If you are a felon, or have ever been arrested on an accusation of a serious crime, that is a future that you're not excited about. If you've ever been in the media -- even on a purely local basis -- for anything salacious, that's not a future you can be excited about. You can probably get Google Image Search results for "[your county] arrested" (worked for a couple of counties that I sampled at random); there are websites like mugshots.com that republish mug shots and details of the arrest.

As it is now, the only thing that ex-cons and others in similar situations have going for them is the relatively short attention span of the public and a vanishingly small support network of other ex-cons and people willing to give them another chance.

The rest of society, for the most part, regards them as unequal citizens (and in some cases, sub-human, depending on the offense).

An apartment complex might choose to rent to an ex-con for some reason; once the technology is available, management will have to deal with outraged neighbors and many apartment complexes will simply stop renting to them. An employer might give someone a job but not disclose that person's personal history to their co-workers; if the technology becomes ubiquitous enough, that will stop being an option too.

I don't think the technology itself is inherently bad. But, I don't think society has yet reached a point of maturity where it can gracefully handle this.