There is an interesting meta-discussion going on here, over whether content curators add value. Most of the hackers that I've met tend to believe that they would prefer to latch onto a raw content stream, then filter and format it to their liking. No surprise -- that is the way of hackers, after all.
However, I do think that it's a conceptual mistake to assume that the public at large would like to filter their own content. Even music sales, which are pretty far down the road towards an openly accessible market, are still driven by the major and minor labels. For books, I see an even stronger incentive to keep paying others to filter our content. Reading is a big investment, time-wise -- when people curl up with a book, e- or paper, they want to know that it's going to be worth their time. And, yes, they probably want it to be nicely typeset and proofread as well.
I think there are many books out there that aren't exactly masterpieces, put out there by big publishers. Conversely, works that are big commercial successes were for a long time shunned by publishers (JK Rowling).
Perhaps user reviews & ratings, and previewing books would be a good enough filter? I mean people can already publish anything they want for free online, and non-techies seem perfectly capable in filtering out.
As Shirky writes, abundance breaks more things than scarcity. Books included.
In the age of constant, uninterrupted information, quality filters will be king. That's why people want news readers that automatically bubble up good shit (badly). That's why people follow others on Twitter who give good link. That's why, in theory, we use HN.
However, I do think that it's a conceptual mistake to assume that the public at large would like to filter their own content. Even music sales, which are pretty far down the road towards an openly accessible market, are still driven by the major and minor labels. For books, I see an even stronger incentive to keep paying others to filter our content. Reading is a big investment, time-wise -- when people curl up with a book, e- or paper, they want to know that it's going to be worth their time. And, yes, they probably want it to be nicely typeset and proofread as well.