I think we may need to define literature.

If by literature, you mean books, then no.
I don't think the Internet will destroy Literature. Through various forums, and emails, I have become a better person, and learned so much more than I ever would have without it.
Although it isn't always evil, I do think excessive computer usage is a distraction and can lessen attention span. Because we're used to typing something into Google and having everything at our fingertips immediately. Also, it's REALLY easy to be on the Internet when you shouldn't be.

So in that way it can be detrimental.
When you come to "intelligent literature" though, things get a little trickier. ANY idiot can buy a website on the Internet and start a cult. Or write about brain surgery whether they are a doctor or not. Through the internet, our culture is exposed to this kind of quackery, and an impressive array of advertisements.
And we've gotten used to this. I would actually say that the internet has made Americans as a people less trusting. (at least in my small, homeschooled, conservative circles.

)