Tip of the week: an important comma that makes a difference

I'll make it short this week; nevertheless it's something I wanted to point out as I've read quite a few self-published books or edited a lot of manuscripts where this particular comma is missing.
For many it might not be important, but it's rather interesting 5o see how the meaning of a sentence can be altered, just by inserting this tiny little punctuation mark. It's used mainly in dialogue, or when the character writes a letter/e-mail; in any case, one person is addressed by name or nickname.


"Could you please explain what you're talking about, love?"
"Hi, lovely blog visitor."
"Hello, everyone."
"I know, Stella, what you mean."
"Stella, it was you, wasn't it?"
"Good morning, reader."
"Thanks, dear buyer of my book."

Here is an example about altering the meaning:
"I don't know Stella." (Someone has no clue who Stella is.)
"I don't know, Stella." (Someone tells Stella that he or she has no clue.)

Okay this should be the small editing tip for today. I wish you all a happy Sunday.