I've heard a lot of times that there is a major difference between saying:
How are you?
and
How are you doing?
Is that true? I've heard one was like an extension of “Hello” and does not mean anything, so you should not answer it with “Fine, thank you. What about you?” but also with “How are you (doing)?” But I just don't remember which of them means what.
Best Answer
In England, "How do you do?" was until recently a commonplace greeting. The correct response was, "How do you do?" This may be what you're thinking of.
Both "How are you?" and "How are you doing?" should generally be taken as a question, to which the reply is often, "Fine, thanks!" or, more formally, "Very well, thank you." However, the whole thing continues to confuse even English people, let alone visitors.