I bought a Kindle in October.
A Kindle is a ebook-focused tablet computer with an e-ink screen. This means the screen isn’t like a normal monitor, lit from the back, but instead changing the page means the graphics stuff draws the screen and then turns off, so keeping the same page up means instead of having to redraw it sixty times a second, you leave it alone. Net result is that eink displays are a lot slower to redraw (you can physically see the screen refresh and redraw), but the display costs nothing to run, so battery life is really impressive.
The battery life on a Kindle is a month of daily use, if you turn the wifi off. If you turn the wifi on, it’ll only last three weeks.
The lack of backlight does mean you can’t see it in the dark, but it does also mean you can read it in bright sunlight. Amazon sell cases with built-in lights. I have one of these, it’s great.
The Kindle does not, will not, has not, shall not force you to buy all your ebooks from Amazon’s kindle store. It reads most ebook formats natively – although doesn’t like font-embedded PDFs very much – and for everything else you can run it though Calibre. If you plug it into your computer it’ll appear as an external drive, and you can put books on it that way.
Books you buy from the Amazon Kindle Store are encumbered with a form of DRM that has not been reverse engineered yet. They will be available to any Kindle software you attach to your Amazon account (The kindle itself, sure, but also the phone, iPad and desktop apps) up to five devices. They are locked to your account, although Amazon are bringing a form of lending service in.
Free books (Amazon offer quite a few of these) still have the DRM.
The Kindle will play MP3s (better than my Desire, as it happens). It’ll read aloud any book that the publisher hasn’t said “that will canabalise our audiobook sales” on (which is, yes, bullshit).
The Kindle has a webkit-based web browser that will happily display wikipedia.
When you register a Kindle on your Amazon account you get a magic email address. Anything sent to that email address from addresses you specify will appear on your Kindle. If you have a 3G kindle this will happen rapidly and will cost you money (based on document size). If your kindle is on Wifi this will never cost you a penny. (There is another magic email address you can send stuff to which will only ever transmit over wifi).
If you read to page 245 of your book and the kindle can phone home, it will tell the server this. If you then pick up your phone or iPad and open the same book, it’ll ask if you want to pick up where you left off on the Kindle. This works both ways.
It comes with minesweeper, and you can buy scrabble for it.
It comes with both an American and a British dictionary to look up words, including ones in the book you’re reading.
It is not “the same” as a normal book. It costs as much as ten new books, it can hold thousands. You can’t see how far you are in it by looking at it (you have to look at the bottom of the screen). You don’t get the feeling of turning the page, but you do get to turn the text size up if it’s too early/late/monday to focus.
Also, it means I always have… 84 possible books on hand right now. And counting.