How far are you, right now, from a copy of the Gutenberg Bible? In twenty seconds I can have the full illustrated text of the original German at my fingertips, as well as a number of translations, annotations, and an exhaustive history. And this isn't a staged test -- it was a random choice, although it seems fitting given the special place that document has in the history of information transfer. I'm guessing you're about the same distance from it right now, if you're reading this on a computer and have heard of Google.
What would the answer to the same question have been twenty years ago? Assuming you're not a scholar specializing in the subject, probably at least five miles, and that's if you live near a book store that's more well stocked than most. How about two hundred years ago? Maybe a couple hundred miles (several days travel) to a large university, or maybe you wouldn't be able to find one at all.
How far are you from the episode of The Daily Show that aired two weeks ago on Thursday? I'm guessing about forty-five seconds because the show's site is a bit hard to navigate, but that's still not bad. Even five years ago the answer would have been anywhere from a couple months to nearly a year, and that's assuming the show in question was ever released for purchase (in this case it isn't aside from some "best of" compilations). The same is not currently true of all television, but there's no reason it couldn't be except that the studios think they can make more money by not releasing them this way.
The fundamental genius of Gutenberg is not so different from what makes computers and the Internet revolutionary. In fact, if you strip away the specifics of the technology the basic statement of each is exactly the same: "this invention makes it easier to copy and transport information". The reason that some things are everywhere, and that more and more things are becoming omnipresent, is that it takes next to no effort to copy them.
Before computers, to get this text to you I'd have to either hire someone with a commercial printing system to create a newsletter, or type it up myself and make photocopies (depending what you define as a computer). Before the Internet, it wouldn't be much better. I'd be able to use a word processor to format the document, but the cost of producing physical copies is still relatively high, and once they're created they'd still be located in one place, which isn't terribly useful. Today, you can get a copy of it in a couple of seconds, just by asking an automated system.
To understand how important computers are, it's necessary to understand what isn't a copy. Television, radio, and phones (at least the old ones), are not copying systems, at least not in any meaningful or useful sense. With television and radio the data you're receiving may come from a copy, but that copy exists in the TV station. Between the transmitter and your television there exists a state of energy in the radio spectrum that does constitute a copy of the information in a loose sense, but the display of that information happens as a real-time reaction to the state of the energy passing by your physical location.
To convert that information into a copy that can be stored you would need special equipment such as a tape recorder. Once you've stored that copy you could use it to recreate the state of the electromagnetic spectrum that causes your display to show that information, but even then between your VCR and your TV there exists only one copy in any meaningful sense. The information transfer systems we had before computers just didn't rely on copies in the same way.
With a computer, in contrast, copying is the default. It's built in at such a deep level that most people don't notice it, or even really understand it. To watch some piece of video or listen to audio on the computer, the computer gets a copy of it and stores it, then it displays it. The information is copied to maybe ten different network appliances on the way to your system, where a copy is stored in memory. It may be copied in memory several times, from the part of your operating system that deals with network transmission, into memory controlled by the application that requested it, and then into another part of system memory for output by the video or sound hardware. It may also be copied to the hard drive as your system rearranges bits of running programs, or caches data for faster access in the future. In between each of these copies the data may be converted into electric signals and back, but each copy is identical to the original on the system you got it from in the first place.
It's easy to miss this, because most of the copies are invisible to the user. Most of them are in volatile memory that is lost when the computer powers down, and even before that most of the copies will be discarded within milliseconds. But they don't need to be. All of these copies could be kept, or copied again to somewhere permanent before discarding them. The system copies and discards data so quickly because in this case it's trying to emulate a reactive system that doesn't use copies. For this purpose, storing the copies isn't necessary. But the copies are there, unlike the systems the computer is replacing.
It's extremely satisfying to me that the revolution computers have caused in our culture is based on exactly the same thing on a larger scale. We're at the start of an information revolution, and the whole thing is based on these fantastic machines that can copy almost any information, which themselves are constructed of nesting levels of copies, upon copies, upon copies. The location and scarcity of information have completely broken down, and I think we're only starting to figure out what that can lead to.