During a discussion of the Creative Class concept, Jon Udell notes in passing that author interview and other book summaries (Meta Book) can reduce readership of the underlying book. ICommented...
I think most (Non Fiction) books are too Fat (Fat Book). Perhaps the future is a Thin Book in print with Hyper Book for detail?
Also, is the goal of Writing ABook only/mainly to have people read the book, or to spread the ideas within the book? Perhaps the book is just an anchor for a looser Conversat Ion (Social Object).
Of course, this doesn't cover the issue of how you get paid for that Conversat Ion (Business Models For Information). But people like Dave Winer and Hugh Mac Leod always point out that they Make Money because of their Web Log-s, but not from their blogs. Similarly, Richard Florida makes some nice change from his speaking fees, etc. (And lots of books get bought but not read...).