1.) Noun. Used in written conversation to express disbelief, incredulity, or lack of response to an outrageous statement.
2.) Noun. Written proceeding a sentence to add implication to that sentence.
1.) Person A: Yes, I did eat the bread that was growing mold. I was that hungry!
Person B: ......
2.) Person A: Have you heard back from the doctor about that rash?
Person B: Yes...... Implication: (And I have an STD) or (And I would prefer not to talk about it).