I'm confused between two kind of greetings in English, "How do you do ? And "How are you ?
I googled for it and found this:
How do you do?
This is not a question. It is another, very formal way of saying "Hello." It is also very British. The correct response is; "Pleased to meet you." or "How do you do." or just "Hello." We only really use it the first time we meet someone.
----How are you?
This is a question, but the person asking it doesn't really want to know the truth about your aching back or hangover. A polite response is; "I'm fine thanks. And you?"
http://www.learnenglish.de/mistakes/howdoyoudovshowareyou.html
But I want to know are they really different in the meaning and use in our daily conversation, especially in terms of British and American English?