First small enough for a laptop but soon after small enough to go anywhere - because everyone will want one and demand will drive down the cost.
This is a very interesting development in the world as we know it for a couple of reasons.
For one, after more than four decades, it may one day dislodge "Typing 1" as the most valuable educational class I ever took. Back in about 1972 or so I needed an extra high school "filler" class so I took typing. It was taught by a very short woman who's goal in life was to make sure that every female in her class could get a job as a secretary. She also taught "short hand" - another now-lost communication art form - as well.
Males were tolerated in her class as long as they were well behaved.
I think it was only a semester long but in the end I could type 43 words a minute - not bad for a guy in 1972.
We used powered mechanical typewriters - another now-lost technology.
But the valuable thing I retained was the skill to type. This has served me well in the decades since when composing email, writing blogs, editing programs, using keypunch machines, you name it.
But Kinect has the ability to change that.
Even the iPad today has a "replacement" touch keyboard so the notion of mechanical keys is on its way out. The Kinect will allow other kinds of motion and movement to be used to drive computer input. For example, instead of fancy 3-D mice you will just be able to reach out over your keyboard and "grab" the 3-D object to rotate it - no more "Ctrl-Shft-Meta-F3"...
Kinect will no doubt create all kinds of other input options as well: 3-D replacements for mice, knobs, buttons, and so forth.
And once Apple gets hold of this there will be even more bizarre gestures possible: "three finger air stroke left-right" to flip the page - so no more trackpads... Turn the page with a blink of your eye.
But there will also, no doubt, be a dark side as well: bots taking over your laptop's Kinect to spy on you.
Whether for your employer or for sinister Latvian hackers your laptop will be able to report whether or not you are in front of it.
Whether or not your hands are moving.
Whether or not you are alone.
Whether or not you are drinking coffee.
Whether or not you are scratching your... the possibilities are endless.
So now, like GPS-spying, there will be need for even more privacy laws because no doubt someone will discover that there is no specific law protecting the privacy of the gesturing (direct or implied) you are doing in front of your computer.
As soon as Kinect is turned into a "chip" it will make its way into cars and smartphones as well.
So your car will be able to tell if your alone.
When you got in and out.
Were you carrying something.
Your smartphone will also know how many people are with you.
You significant other will be able to use this to spy on you.
And though today you need permission to record audio of someone, like the HAL 9000 of 2001, your Kinect-based laptop or phone will probably be able to read your lips (thanks to some do-gooder helping the challenged) - you can look it up if you don't know what happened as a result of HAL's lip reading.
Now more laws will be required: the Kinect Anti-Lip-Reading Law - for example.
Initially it will be used to replace the need to text with your hands - the phone will simply read your lips (while hearing what you say to confirm) and text for you.
There will be a slew of home-based security widgets: Instead of the security company having a visual of your kid entering the front door the Kinect will scan them for dope - oh look mom - there's a glass pipe concealed in that kids hand...
While I personally think the Kinect is a very cool innovation the more I write this blog the more I realize what level of idiocy it will create - the very least will be new "Kinect" laws.
There are enough laws already and we don't need more.
If you're a moron then "Kinect" technology will only enhance your ability to be a moron - not diminish it. So you'll become a more powerful moron - able to screw up even more with less effort.
When computers were first used commercially in the 1950's no new laws were required. It wasn't until much later that special "laws" were needed, e.g., patent law for software.
But I think that the real reason is that people's morals decayed and the computer became a tool for greed and, in response, the law changed address the problem - but only superficially because, unlike HAL, computers can only be used for evil by evil people.
The "Kinect" will be "just another brick in the wall..."