The two phrases are very similar. After you have answered a question, either can be used to ask the other "And you?" A: How's your day been? B: Good, and you (what about you or how about you) A: Not too bad, thanks. A: Where are you from? B: I'm from the US, and you? (what about you or how about you) C: Japan. They are pretty interchangable when the question has already been asked. Alone, they make little sense. A: What about you? B: What about me???? A: How about you? B: How about me???? Asking these questions alone will leave a person confused.

Of course, you can use "what about you" when you have told your name to other one. However, "what about you?" is meaningful unless someone has mentioned something. " what is your name?" could be utilized independently without any statement above. "how about you" : what do you think of If you say you live in japan and wanna know their hometown, 'what about you?' is same meaning as"where do you come from?

"How about you" and "What about you" are not really used to ask someone's name. They are more often used to discuss things happening in someone's life, or to ask someone what they have been doing recently. You use them to make conversation with someone. Asking those questions prompts people to start talking or telling a story. Examples: Person 1: How are you? Person 2: I've been great, how about you? OR I've been great, what about you? Person 1: I just spent my vacation in New York. What about you? Where did you go? OR I just spent my vacation in New York. How about you? Where did you go?