The three periods in a row is called an ellipsis. I use it quite a bit (incorrectly) myself. It is used in writing to indicate an incomplete thought or to lead into or out of and incompleted quote. It is supposed to indicate a slight pause in speech or any other form of text, but it is incorrect to use ellipses solely to indicate a pause in speech. That is how I use it, incorrectly, sometimes when I am posting, to give a sense of conversational reply. I know it is wrong...but I suspect I may resort to it from time to time
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