Let me try to give a shot on the AR...
Augmented Reality is quite misunderstood concept IMHO. I have been involved with design and implementation of quite many different kind of VR and AR systems over the years. And I always felt uncomfortable with the technology and what emphasis people put on the tech instead of for what purpose this tech is used.
One big problem for me personally was that none seemed to be able to explain why VR/AR are useful. Intuitively everyone has such fascination and awe, but when it comes to explaining things everyone went mute. Hence I started to try answer that question my self. This being only my personal point of view on things, more of and hypothesis over some 5+ years of empirical observations
On that basis, I gave lecture on Augmented Reality, introducing framework how I see VR/AR when developing different kind of systems mostly for industry. In more general sense the principles of this framework are also applicable to whatever kind of applications you develop. Even VR/AR games and where you put the challenges or push your player to the limits, for example Cymatic Bruce experience in Portal 2 when jumping off the cliff down to grab a box etc. Or when it comes to the use of Google Glass in comparison to Meta 1 for some GPS based adventure game or educational app.
I hope this lecture provides some structure when you try to understand what makes VR / AR games or applications either fun and engaging or from serious games point of view what makes them useful (Since you can do basically everything but that does not warrant value for industry).
In the recent Augmented World Expo 2013, many of the key players in AR field debated whether Google Glass is AR solution at all, or if Meta 1 is the true AR system. This debate also revolved around work conducted by Steve Mann on the perceptual enhancements. And I hope if you see my lecture it should become obvious that this starts to look like apples vs oranges kind of debate, hence not very constructive or useful arguments.
Please feel free to throw feedback. As I say in the video description this should also stir some discussion within the AR community what we are trying to achieve with our technology.