After my time in Peace Corps, I never ask this question. Even if you don't think the question is about class, income, or social status, many other people do. It's as rude a question as asking "What are you?" Instead, ask "What do you like to do?" or "What music do you like?" or dozens of other far more interesting questions. Too many people don''t have traditional jobs these days. Besides, if someone answers, "I'm a dentist," you haven't really learned anything about them. Ask something interesting, and you will be perceived as interesting yourself.