它们的意思一样。它们都是“呢”的意思, 但是它们总在句子的前边。

There's no difference. By the way is Hmwmp your name, or is it some sort of an emoticon? :)

How about you: refers to personal things, feelings "How are you?" - "I'm OK. How about you?" What about you: refers to things which are not personal "Where do you live?" - "I live in London. What about you?"

what about 和 how about 意思是差不多的，都是表示询问意见的，但是what about 后面一般接名词，how about 后面一般接句子。