It used to be that if one wished to keep a large store of information that they would need to build a library into their home, and take precautions against the attacks of insects and the yellowing of age.
Now, if a novel takes 2 megabytes of storage space, you can get 328 of them on a single CD. Encyclopedia Brittanica is available on a single CD, as well as something called "The library of the Future". And you can get approximately 10 times the amount of storage of a CD on a single-sided single-layer DVD. You can truly carry a library in your knapsack, and save paper by the ton in the bargain. Careful organization of folders and subfolders makes it possible to find any book nearly instantaneously.