Well, as is stated in this article, everybody is already writing. This doesn’t mean that everyone is writing books, or scholarly articles, but everyone is writing things down.
Facebook and Twitter allow people to post their thoughts in short snippets, whereas people use blogs when they have something more to say. With everything that is online, there is no way that one person could read it all, but because everyone is a writer, there is a variety of stuff out there to read. Whatever you are interested in there is probably people blogging about it.
With the ability for everyone to be able to write, we see the way of writing shifting. You don’t have to have an editor to get things published, you just hit post. Also, we don’t see a lot of long articles online. Writers cater to what readers look at which is a couple sentences, more if they are interested. I think we see a lot of short writings online because that’s what people have time to read or care to read.
As long as the internet keeps booming, I’m sure people will continue to write. I think the shift is in the technologies they are writing on. First we saw pen and paper shift to computers, but the next shift it seems will be going from writing on your computers to writing with your cell phone or smaller portable computers (netbooks/iPads).