Qi Lu, Yahoo's top search scientist, has been rumored to be leaving the company since June. But he's only just recently disappeared from Yahoo's list of top executives. We hear he's taking a job at Microsoft. Microsoft, the land where Web talent goes to die?Yes, Microsoft. The software house is desperate to catch up with Google, and Lu was one of Yahoo's few standout talents. Nevertheless, Lu's rumored choice of employer is surprising. Kara Swisher spotted Lu dining with David Sze, a partner at Facebook investor Greylock Capital. At the time, she speculated that Lu might take a cushy entrepreneur-in-residence gig at Greylock — or fill the empty CTO spot at Facebook. The fact that Facebook has yet to name a new CTO suggests they were holding out hope of landing Lu. For Lu to pass on the job would be telling. A year ago, Facebook could hire anyone it wanted, and they wouldn't have spent months dithering. if Lu takes Microsoft's job offer, it will show that Mark Zuckerberg's engineers-first culture at Facebook is fading fast.