Many of the products we buy today are no more than large collections of zeroes and ones. High-priced software, high-quality music, and valuable reference material such as computerized databases or CD-Rom encyclopedias are commercial products like any other, but the media of their transmission makes them different in at least one aspect: it is possible to copy them freely, or at least extremely cheaply. A compact disc of Elvis Costello and the Attractions is different from, say, a ham and swiss sandwich in many ways, but beyond the obvious is one reason that makes the nature of the two items and their production and purchase very different indeed: I can only eat the ham and swiss sandwich once, while I can listen to the Attractions CD repeatedly. This is a result of the fact that the CD contains information, rather than an actual substance such as the sandwich has. The consumable material in the sandwich is actual food and is gone after its consumption, while the consumable material in the compact disc is encoded binary data that will be around for the life of the physical disc. Since the sandwich can only be consumed once, we pay out an amount of money that signifies what one sandwich is worth to us. If I want another sandwich, I pay another $4.95. If someone were to invent a ham and swiss sandwich that could be eaten thousands of times (let's not go into the mechanics of how this would work) then the producer might be justified in charging many times the cost of an ordinary ham and swiss, on the grounds that I'm getting more than just one sandwich. "Buy our sandwich once, and you'll never go hungry again!"
             However, one might protest this idea if we know that it still costs the usual amount to make the sandwich. If a producer can make a repeatedly-edible sandwich for a couple dollars, and sell it for $4,000, he stands to profit hugely. The reason we might be able to justify charging four grand for a ham sandwich is that in our usual...