Blurbs or Blank Back Covers?

Levi Asher feels that a book must have some copy on the back cover, like blurbs or review excerpts:

I still feel strongly that back cover blurbs and review excerpts are essential to the "selection process" every reader goes through when looking at a new book. A publisher who presents a blank back cover on a novel by an unknown author, in my opinion, must not be thinking about how potential readers are going to look at this novel. The purist approach Chapman describes sounds admirable, but I don't think it translates into reality. I am simply not going to devote my time to reading a book without some idea why I should read it. A novel needs a road map, and to fail to provide some explanatory text when publishing a new author is, in my opinion, a fatal mistake.

But Daniel Green from The Reading Experience disagrees:

Frankly, I almost always ignore not only this back-cover material, but everything that's printed on a book jacket, including the flap copy. My curiosity about what I will find in a given book is going to be satisfied only by reading a few paragraphs, a few pages, enough to inform me about the book's thematic focus and aesthetic assumptions. Sometimes it won't be safisfied until I've read the whole thing. (Sometimes it will be satisfied quite quickly and I'll decide it's not a book for me. But the blurbs and the review excerpts will have had nothing to do with it.)

I'll have to agree with Levi Asher if the book's shrink-wrapped (like in Kinokuniya or MPH), and with Daniel Green if the book is not (Borders or Payless). But I would prefer thumbing through a book to see for myself if the writing was good enough for me to get it or not.