Librorum istic inopiam esse quereris. Non refert quam multos sed quam bonos habeas: lectio certa prodest, varia delectat.

Sen. Ep. 45.1

I have been trying to compile a catalog of the books on my shelves for a long time. It seems important, both from inventory organization standpoint, but more from a "Show me your bookshelves and I will tell you who you are" standpoint. (I will be talking about books here; the situation with CDs is even worse (a lot worse, actually)).
At first I thought the most difficult part of it would be to create the tool for managing the catalog; but I soon realized that the actual going through all the shelves was so time-consuming as to be prohibitive.
The advent of networked tools such as LibraryThing has made it a little less daunting. The current catalog lists, mainly, the most important nonfiction parts of my collection which are directly relevant to my work.

As Arnold Dolmetsch excellently explains:

...Both the German and the French versions are in my library, as well as most of the other works quoted in these pages. And indeed if I had not been the owner of these precious books I could not have accomplished my work, for it is only by studying them again and again, at leisure, for years, that the light has come to me.

Alan Kay says in this ask-me-anything:

There are more than 23,000,000 books in the Library of Congress, and a good reader might be able to read 23,000 books in a lifetime (I know just a few people who have read more). So we are contemplating a lifetime of reading in which we might touch 1/10th of 1% of the extent books. We would hope that most of the ones we aren't able to touch are not useful or good or etc.

So I think we have to put something more than randomness and following links to use here. You can spend a lot of time learning about a big system like Linux without hitting many of the most important ideas in computing — so we have to heed the "Art is long and Life is short" idea.

Part of the "Oxbridge" process is to have a "reader" (a person who helps you choose what to look at), and these people are worth their weight in gold ...