Book jacket blurbs

Answers.com says this about a blurb:

blurb (blûrb) n.
A brief publicity notice, as on a book jacket.
[Coined by Gelett Burgess (1866–1951), American humorist.]

Aurora award-winning author, editor and educator, Robert Runte--in a comment to my previous post (April 12, 2007) in which he trashed the description of my book, brought up a good question about book jackets. What's appropriate? How much detail is too much? How much is too little? And does it depend on the genre? I've seen some very long and involved blurbs in some fantasy covers (i.e., Marjorie B. Kellogg's Dragon Quartet; Jacqueline Carey's Kushiel's Dart just to name a few). Then there's SF, with usually a shorter blurb accompanied by reviews and short bio (e.g., Stanislaw Lem's Solaris, so many others). Although I agree with Runte, I had to research this further (remember, I'm a scientist). So I asked one of my primary resources at hand: my son. He replied that when he browsed a bookstore, after letting the cover and title (if not author) draw his attention, he immediately went to the back jacket; he preferred a fairly short to-the-point description that gave the gist (and genre) of the book (enough to intrigue him) but not so much that it made him yawn (oh, dear), and he liked seeing comments by reviewers (preferably short). I then pursued my secondary source: Google. I found a delightfully blunt though insightful discussion by Lynne W. Scanlon, "The Publishing Contrarian" (here's the URL: www.thepublishingcontrarian.com/2006/11/10...). In her opinion, jackets totally sink or sell a book. If the book jacket failed to ignite the interest of the bookstore browser, they wouldn't bother to take that critical next step of peeking at the first paragraph of the first chapter before tossing the book back on the shelf. Her point: the story can't sell itself. While she may be mostly right (I like to think that word-of-mouth sells a story very well, book jacket and cover aside), certainly where a potential reader is first encountering a book and/or writer, that first impression is critical. My own preference is to see something genuine about the story and tone of the book and not be led astray (something that has certainly occured...another reason for Runte's 'less is more'). So, what do you, the reader, like to see in a book jacket description? What grabs you? What stinks?