It's not that often electronics can change your life — but it happened to me a few days ago, when I bought an Amazon Kindle.

If you don't follow consumer electronics, Kindle is Amazon's e-book, a device about the size and weight of a small paperback that stores approximately 200 digital books. Yeah, we've been hearing about the "dawn of the e-book" since, oh, approximately 12 B.C. (when PCs were the Next Big Thing). But Amazon's really nailed it: Not only is the device sleek, polished and easy to use — it's online all the time, so you can purchase books with the click of a button. There's no subscription service (Amazon covers the cost of the wireless network connection). And books are generally flat rate, at $9.99 a pop.

Kindle takes instant gratification to a whole new level: See-want-buy-read, all in a couple of minutes. The company also has actually figured out how to make online purchases easier than peer-to-peer piracy. (More on that in a second.)

As soon as I figured out how to work the device (which took approximately 30 seconds), I told the books lining my floor-to-ceiling bookcases: "So long, guys, you're obsolete."

OK, maybe not quite: last I checked, Quantum Mechanics by Ashok Das wasn't among the 130,000 titles available in the Kindle store, so I'll keep the print version for now. But give it time. Publishers are just beginning to grasp the notion of e-rights distribution —but they're learning fast. (I've heard that some publishers have sold more in the first quarter of 2008 than in all of 2007, because of Kindle).

Then I started to wonder why it took the world so long to come up with my other favorite life-changing invention: satellite radio. I've got XM at home, online and in the car — and I happily pay a couple of bucks a month for being online, all the time. (I'm still waiting for one of the cable companies to start streaming "Law & Order" to my cell phone 24/7, but I'm certain it's just around the corner).

Here's why all this matters. Slowly, haltingly, companies such as Amazon are cracking the code on how to sell content profitably online. The format's simple: Keep customers online, all the time. Make purchases dead easy. And charge flat rates. Do it right, and you'll even avoid peer-to-peer piracy (which has always been more about convenience than cost-savings).
Unfortunately, just as content providers are figuring it out, carriers are going in the opposite direction. The major ISPs recently announced plans to price by the byte, at least for heavy users. As any economics 101 text will tell you, a metered-usage approach discourages users from purchasing services.