Salutation Punctuation

I specifically remember learning this punctuation in grade school and high school:

Hello, Dolly. (Hi, John.)  I remember learning to put the comma after a casual opening, but if it was "Dear" or "To", etc., you would not put the comma there (Dear John, -or- To Whom It May Concern: ).

Now it seems as if everyone is writing:  Hello Dolly or Hi John - with no comma.

Can you tell me if I am remembering incorrectly or if this is "old" punctuation style that has been abandoned?

Thanks,

Cora

I'm sorry, but that was totally not what I was looking for...

The reference to the used comma is the one that is BETWEEN Hello and Dolly:  Hello, Dolly.

As far as other punctuation, that is not my concern but thanks for the response anyway.

I specifically remember this, too. i was told by a former boss it was "Ungrammatical" -- why did I listen to that idiot? I finally did a little research and found the comma is indeed grammatical.

I am 26 and from the Midwest; I was also taught the "Hello, Dolly" and "Hi, John" approach.  Although now that I am in the professional world on the East Coast I must say, although I still use it religiously, I rarely see it in other people's writing.