In an ATMB thread I just posted to, I was talking to Q.E.D. and ended a sentence with his user name and didn’t know how to end the statement. A period seems obvious but since his username ends in one, would it have been proper to end it like normal and make it look like I was trailing off instead of ending the sentence?
Customarily, a period/full stop occurring for other reasons than punctuation and the period/full stop ending a sentence are consolidated into a single punctuation mark, with one exception. Since the mark of an ellipsis is three such dots in a row (…), it is customary to add a fourth one to indicate the end of the ellipsis and sentence. E.g., “When in the course of human events … among these rights are life, liberty…” However, “I am glad you referenced Q.E.D. His statements are confirmed by this cite from the A.C.L.U.”