
Originally Posted by
pablo2607
I suppose it depends on who you are writting to, of course, but no matter, to me it sounds corny, nor have I heard of anyone using this introduction. Personally I would say "How are (How're) you doing old buddy?".
On the "How do you do?" formula I would say "How do you do sir?, if you are trying to be formal. In any formal letter, the "Dear Sir" is always recomendable.
Bottom line, in a letter you can express yourself in any way you want as long as what you are trying to say is understood by the receiver.