Amazon’s got wikis
I just stumbled across this, but it seems as if it’s been around awhile (as described at urlgreyhot for the great book Information Architecture for the World Wide Web by by Louis Rosenfeld, Peter Morville). The amazon page for The Singularity is Near, by Kurzweil has discussion features and a wiki feature! The wiki feature is described pretty well. There are no entries in the wiki for this book yet….