This is something I have written about here and here.
Think the idea is gimmicky? Think again, and understand what's coming. This is the internet (and then some) right in front of your eyes and in your ears. No need to fish your phone out of your pocket. Robert Scoble, a tech guru, has been trying out a pair for a few weeks, and he says he'll never again be without them. You can read about him here.
What do they do? Well, you can photograph or film anything you're looking at hands free. You can get turn by turn directions. You can ask them anything (voice recognition is built in). You can pull up the internet right in front of your eyes. It appears to hover a couple of feet in front of you, not in your direct line of sight. You can read or send emails and texts. But that's only the beginning.
For a fun video that highlights some of this, click here.
Remember, if you're old enough, back when the Apple II hit the market. It did absolutely nothing useful, but a lot of early adopters bought them anyway. Very quickly, software developers made them, and other PCs, highly useful. Suddenly, it wasn't a case of wanting something, but needing it. You were at a disadvantage without one.
Or how about in the late 90s, when cell phones started gaining popularity? Many resisted, particularly the middle aged and older, thinking it completely unnecessary - annoying, even - to always be "available." Now, there's a societal expectation that you have a phone, and that's because they have become indispensable. Of course, along the way they got "smart" and even more ingrained into everything we do. The App Store is now approaching its 50 millionth download and the iPhone hasn't even been around for six years. Apps were almost an afterthought.
All this will happen with Google Glass (and presumably an Apple competitor). The development community will flock to Glass like Michael Moore to a donut. Tens of thousands of new applications, ones we can't even dream of, will be introduced, and many of them will become integral to our daily lives. Many will do astounding things, like merge what you're seeing with virtual reality. You will be at a disadvantage going about your daily business without your Glass.
Yes, the early adopters will look like geeks, but that won't last long. If the product is priced in the $200-300 range, as is rumored, it will go viral quickly.
Portable, augmented intelligence, currently represented by the smartphone, is effectively becoming our sixth sense because it connects us directly to the entire world, wherever we are. As I've written before, history will someday be divided between the time before this and the time after. Google Glass is the Next Big Step.
P.S. This device will introduce us to a veritable tsunami of privacy issues, but that is a whole other post.