Imagine the entire Internet for a moment, with information zipping rapidly from one place to another. Frozen in time, all of the information in transit is stored in that giant web. You can't get it out very efficiently, and it vanishes in a moment, but what if you solved these problems? Now imagine that all the fiber in the Internet is lined up as one long fiber-optic cable. It wraps around the earth numerous times. Connecting both ends of the cable is a special device, called a repeater. As incoming light strikes it, the repeater detects it and repeats the exact same pattern out the other end. Pretty soon those pulses wind around the earth and strike the repeater again, and are once again repeated. Now we have a very rough way of storing information. Now imagine another device, called the reader. The reader can ask the repeater what pulses just went by, just like the read head on a CD-ROM asks what groves are carved into the CD below it. One more device, the writer (which can introduce new light pulses into the system) and you've got a permanent storage device. How much information could it hold per earth-coil? How heavy would the cable be? How much would it cost? Don't ask me, I just think these things up!