Google Glass is a wearable device in the shape of glasses with a small screen and a camera at the right top of it developed by Google. The good thing about it is that you can communicate with the internet, take pictures, record videos, and do many other functions via voice commands. From my point of view, it's fascinating, as I see it as a huge step for technology. It can be interesting to do everything you can do with a smartphone hands-free.
On the other hand, there's always the price issue. It is said that the price won't go below $500 in 2014 - which is far from what most people can afford - and won't be worth it because of the lack of apps at the beggining.
In any case, I'm quite convinced it will be very successful by the year 2016 - if there aren't loads of competitors by then.