This weekend I read Robert Scoble's two-week review of Google Glass.
He makes two pretty bold statements:
1. I will never live a day of my life from now on without it (or a competitor). It's that significant.
2. The success of this totally depends on price. Each audience I asked at the end of my presentations "who would buy this?" As the price got down to $200 literally every hand went up.
But "who would buy this?" is a very different question to "who would wear this all the time?".
The question of whether voice-controlled internet HUDs are in our future is probably an academic one (they are) - the real issue is how widespread will their adoption be, and crucially: in what situations will it be 'normal' to wear one?
I think Google are seriously barking up the wrong tree by implying it could or should be something we would wear and use in every day situations like walking down the street or hanging out with friends. Here's why...
Voice control is a bit rubbish
The technology for voice controlled appliances has existed for a long time, but - to use the simplest example - we don't control our lighting this way, even though it might be more convenient some of the time.
Neither do we control computers this way. Siri and Google voice search have a measure of popularity but by far the most common use case is whilst driving. If and when full speed conversational voice comprehension gets beyond 99.99% this might change, but that's a good while away yet.
See also this recent piece in the MIT Tech Review: Your Body Does Not Want to Be an Interface.
Overall then, I think there is good evidence that people prefer to use their hands over their voices to interface with... well... almost everything.
Also, aside from a few super-simple initiation-type actions (taking a picture, recording a video), I would be surprised if there were many tasks that, even whilst wearing Glass, couldn't be completed more quickly by pulling out your phone.
Wearable devices... on your face
Think about bluetooth headsets. Are they more convenient than holding your phone up to your face? Yes. Do they (still, after over 10 years on the market) make you look like a bit of a douche if you wear one walking down the street? Yes. But are they perfectly acceptable in situations where talking hands free is safer and preferred? Sure - I don't bat an eyelid if I see a truck driver talking into one.