Had the same experience at Amazon a couple years back. They flew me out and introduced me to the techs. I was introduced as "the new admin" and got lots of "so, when are you starting?" comments, like it was a done deal. Then they tried to get me to interview with some random exec... I think he missed about four interviews before HR finally decided to skip him. Couple weeks later they sent me a letter telling me they'd decided to pass. Oh well, I got a free tour of an Amazon fulfillment center and I didn't want to live where it snows anyway; they don't teach you how to deal with that when you're raised in Southern California.
I went on to get a job with another decent sized internet site. My new manager told me that he had briefly gone over to Google, but had been recruited back weeks later. He didn't have a PhD so he felt he wasn't respected by coworkers.