How much is having Google on your resumé worth? Apparently 20 percent more — on your used bookshelf. On Craigslist, a white Ikea Expedit bookshelf, previously owned by a Google employee, is selling for $120. The ad even touts its "true Silicon Valley heritage." Meanwhile, at the far southern edge of the Silicon Valley metro area in Gilroy, Calif., a similar bookshelf is selling for a mere $100. Call it the Google premium.