How cover art influences book sales (at least, for one picky reader)

Guest blogger Jason Sanford often rants on his website at www.jasonsanford.com. His fiction has been published in Interzone, Year's Best SF 14, Analog, Intergalactic Medicine Show, Pindeldyboz, and other places, and has won the 2008 Interzone Readers' Poll and a Minnesota State Arts Board Fellowship.

Here's a simple story about how important cover art is to an author's book sales. There's this struggling new writer named John Scalzi, who has a first fantasy novella coming out called The God...