(1) All sorts of information and collaborative filtering. Examples: Netflix, Amazon, Pandora, etc. Lots on ML in defense these days too -- i.e. here's everyone'

(1) All sorts of information and collaborative filtering. Examples: Netflix, Amazon, Pandora, etc. Lots on ML in defense these days too -- i.e. here's everyone's call data, who's the terrorist? (2) If you just want to implement or tweak existing algorithms, it doesn't really matter what your background is -- the qualifications are the same as any software engineering job (so CS degree helps a lot but not mandatory). If you want to be in a research type position, you'll need a PhD in CS with a dissertation on ML.