I did some back of the envelope math on Q4. If Q3 to Q4 operating expenses rise on roughly the same percentage basis as 2011, then Amazon must post at least $23B in revenue to break even. With all the various and credible reasons mentioned on the board for a revenue miss, it seems reasonably probable that Q4 is at the bottom of the range or worse. Losing a couple hundred million in Q4 will not be positive for the share price.
I think the rise is from two things: the fiscal cliff "resolution" rally and the Apple unwind. There must have been some massive long Apple : short Amazon, Netflix, S&P 500, etc. trades on that had a forced unwind last week. Eventually the math will win, when is the question. Q4 earnings on Tuesday is a very good opportunity. I can't remember a quarter in recent years where Amazon faced as many headwinds as they do right now.