>There is so little on the internet that is unique...
That statement simply _will_ not be believed in this venue. Our experience says otherwise. I've posted unique material, and I know tens of thousands of other people who have. If you're not seeing unique material, you're looking in the wrong places, or not recognizing uniqueness when you find it.
>and this word can be used anyway wanted.
When you want to be understood, you have to use it only in the conventional sense.
>Why is uniqueness an issue?
Uniqueness isn't _an_ issue. It's THE issue. Computers are perfect copying machines. The web is simply a distributed copying machine. But you have to find what you want, to be able to copy it.
So a directory is a way of finding things you might want to copy (for your own archives, or just to read and dump.)
Now, since computers are such good copying machines, there may already be multiple copies of what you want. They're all exactly alike, none unique, right?
Wrong. One instance is by a real person. It's the original, and only one can be original. The original is about what the real person knows, what he's done, what he'd do for money. It's unique because nobody else knows the same thing and does the same thing for money. It's authoritative because nobody else CAN know exactly what he'll do for money--and that makes HIS original version unique. HE can change it, every time he changes his mind about how much money he wants, or how much he'll do, and his new version supersedes all copies, whether or not THEY are ever updated.
And all the other copies ... are just copies. There's nothing unique about them.
That's how content is unique, no matter how many copies of it exist.
So anyone can create a unique website, by taking advantage of his inherent personal uniqueness. And, of course, anyone can create a website by plagiarizing content from other sites. There are tens of millions of spamvertising doorways that exist only to drive content to another site. The only thing those website owners have to say is, "If so-and-so does something for you for money, I want some of that money." Unfortunately, that's information nobody cares about.