I think all positions (SDEs, Business Managers, Marketers) in Amazon's oldest retail businesses (books, consumer electronics, kitchen, home etc.). These are businesses where Amazon has significant market segment share (for example, according to some research out there, in books it is ~80%). So it is natural to think: how many people do you need to keep the lights on? Maybe 5 years ago these businesses needed 100s of people, but with with 80% market segment share, do these businesses need the same number of people? My thinking if I were Jeff would be: If I reduce head count in these businesses, how much more free cash flow would I generate (assuming there is not much room left for these businesses to grow)? In other words, in businesses where I have the highest market segment share, how many people do I need to continue to keep that share. And, if people can be moved elsewhere to higher growth areas, then why not? If I need to move them back to books and electronics at some point in the future, I will.

Disclaimer: I'm an Amazon employee, but the comments here are my own.