This is a question I feel the internet age has engendered, in relation to both fiction and non-fiction. I’ll tell you why.
Let’s say it’s 40 years ago and you’re writing a book on auto repair. You’re describing a particular procedure and realize that before a person could engage in this procedure they would need to replace their radiator hose. So, you write up a whole section on how to replace a radiator hose. And it’s pretty useful; without it your readers would have to put down your book, go to the bookstore and find a book that explains the radiator hose replacement procedure.
Now, in the modern world of interlinked hypertext you wouldn’t need to include that section, you could just link to any of the numerous sources on the web that explain how to replace a radiator hose.
And, frankly, with this in mind you might realize there’s no point writing your book at all. Unless you are really discussing some aspect of auto repair that hasn’t already been covered in some other easily available source, you would really just be creating redundant information. And information these days, with the web, ebooks and such, is much more “easily available” than it’s ever been. (There is, admittedly, a challenge in searching through all that information for trustworthy and correct information, but with a little tenacity it’s doable.)
How about fiction? Certainly every fiction book is in some sense unique. But as I’ve mentioned, I’ve been doing a little work in the realm of book promotion these days and one thing I’ve noticed is that everybody and their dog has written a fantasy novel about a plucky band of dwarves/elves/humans that go off on a mission to free their land from the dark force that emanates from a great tower/mountain/city off in the distance. They’ve also all written novels about a hard nosed detective type with a flaw (alcoholism, self-loathing, pedophiliac tendencies) who has to go up against a serial killer of pure evil (and in the process redeem themselves.)
Are you really doing the world any kind of favor by writing these kinds of books? I would argue no. In both cases – redundant non-fiction and trite fiction – you’re basically creating more noise, more junk people need to wade through to get to the good stuff (like my work.)
So should people just stop writing altogether? Well, I doubt that’s going to happen. But I hope they consider what they are really adding to “the commons” before taking pen in hand.