Putting one foot in front of another can get you a lot of places
It's basically a three pound notebook computer that is less than an inch thick when closed, yet still packs a 13.3" LCD screen and a fullsized keyboard. I won't go into the full set of technology tradeoffs they had to make to get to those figures, but the guided tour does an excellent job of walking you through them:
Like Tom my immediate reaction is I want. My second reaction, however, is to wait a year or three until the technology is a little more mature and the hard disk sizes increase. Right now the largest drive you can fit it with is an eighty-gig model. Not bad, but I'm already growing out of the eighty-gig drive I use for a primary on my home machine. Don't ask how much of that is just files for work- the answer is horrifying.
More interesting is the solid state drive option. Basically, Apple has built a hard disk out of what amounts to flash RAM. The result is that you can fit the Air with a drive that has no moving parts. As this computer lacks an optical drive, that means that aside from the keyboard the only moving parts are the cooling fan. That's pretty awesome- especially for plane rides when unexpected turbulence always has a chance of wrecking your drive's platters.
Beyond that, however, it's increasingly clear that we're moving towards the point when it will be practical to reduce the size of a substantial amount of processing and storage capacity to the point where it could be implanted into the human body. No, seriously, hear me out. Imagine for a moment that we could install a socket about the size of a paperback book into your lower back. Into this socket we could insert a sealed package of electronics containing CPUs, hard drives, RAM, and so forth. Once in this socket it could feed audio directly into your auditory nerves and video directly into your optic nerves. We could even interlace the computer's output with your actual vistion, essentially giving you a heads-up display. Control could rely on manipulation of icons with your eyes, subvocalization, even minute muscle movements in the hands. Integrate wireless connectivity and, hell, even a cellphone and you can be connected to online databases anytime, anywhere. If and when technology moves on, no problem- just remove the old module and install a new, more advanced unit. The only permanent parts are the interface socket and its input/output system to the host.
Why would someone do this? Why not? Imagine the advantages if police officers could access and display images of wanted criminals every time they made a traffic stop. Imagine what a visit to the doctor would be like if she could access diagnostic results, search medical databases, and view patient history without needing to turn away from the patient. How about surgeons who could have their normal vision augmented with fluoroscope output. Do you like GPS navigation systems for cars? How about a system you could carry with you that projected visible icons right into your vision so you don't have to look away from the road? For that matter, how about cars that can use your internal computer to project speed, fuel, and status information into your eyes for the same purpose? The possibilities boggle the mind and, like most other computer technologies, won't be fully realized until we start actually using the system.
There would, of course, also be possible downsides. Power would be an issue, most likely requiring a second socket for a battery pack. It might be possible to run the thing on body heat but, really, that would require a hella efficient system. Using body heat for power would also make one pretty hungry after a hard day of computing since you're more or less running your computer on your body's metabolism. Heat would also be an issue- the system might require some sort of active cooling system that could dump heat into your body for removal in the customary way. There would also be the increased dangers from malicious software. Viruses are annoying right now, but a program that could throw static into your vision or hearing while driving is downright dangerous.
As someone who teaches college students, I also shudder to think what all this would do to higher level teaching. How do we teach when our students might be watching us or might be playing sudoku in their virtual vision? For that matter, writing tests that don't rely on rote memorization would become utterly necessary, but that would probably be a good thing for us all. Finally, the divide between the haves and have-nots would only get worse. How does someone without an internal system debate someone who has one?
The possibilities are amazing, as are the dangers, but it'll be interesting to see what happens. The Macbook Air is only a single step towards such a future but, really, one step after another can get you a lot of places.