One of the professors in my school, Steve Mann[1], is notorious for working on wearable computing devices for three decades now. There's a small group of niche hackers[2] who are into this kind of thing, but it's definitely not a new phenomenon.
http://3.bp.blogspot.com/_sqPHIOY4PBQ/TTtAjzFy6TI/AAAAAAAAAv...
http://hci.stanford.edu/courses/cs547/Resources/Pictures/tha...
What about that HNers who lamented that a Google wearable will be plastered with ads, what if it reduced the overall number of ads you saw?
>"it's definitely not a new phenomenon" Agreed 100%, but Google and Apple could push it into mainstream...and for most people, I'm guessing that it'd be their first encounter with AR / VR.
[1] http://www.media.mit.edu/wearables [2] http://devaul.net/