In this interview at Salon.com Clay Shirkey talks about the future of the book, the reader and the writer:

We have this whole complex of words, "publish," "publisher," "publicity," "publicist," that all refer to either jobs or the work of making things public. Because it used to be incredibly difficult, complicated, and expensive to simply put material into the public sphere, and now it's not. So I'm comparing it to literacy -- literacy used to be reserved for a specialist class prior to the printing press, and, much more importantly, prior to the spread of publishers and the rise of a real publishing industry.

what happened to literacy in the 1600s, 1700s and 1800s is that it went from being reserved for a specialist class to being a general feature of the middle class. The same thing is happening to publishing -- the ability to put something out in public is becoming more important to society, but the delta between "I can put something out in public" and "I can't put something out in public" is no longer so great that you can automatically make money simply by having access to the means of publication.

This is a a technological change whose ramifications are mostly cultural with culture lagging the technology:

So the ability to publish, the ability to put things in public no matter who you are, as long as you have access to, again, a public library or an Internet cafe -- that's a technological change. But the change in perception and reaction to what gets published and why, that's the cultural change.

if there is any intrinsic value in writing or expressing yourself or taking a photo, it's worth doing even if the results are mediocre. Whenever the production maw has opened more widely, whether it's cheap photography or it's weblogs, the average quality falls. The average quality of a piece of writing is now lower because the denominator has exploded. The question becomes how do you find the good stuff in this much larger group. I am not somebody who believes everyone is equally talented; talent remains unequally distributed. What's interesting now is that the old gatekeepers for identifying, anointing, and promoting talent are different in this generation than they were previously