[found on thepunctuationguide.com]
. . .
“An ellipsis is a set of three periods ( . . . ) indicating an omission. Each period should have a single space on either side, except when adjacent to a quotation mark, in which case there should be no space.”
“The em dash is perhaps the most versatile punctuation mark. Depending on the context, the em dash can take the place of commas, parentheses, or colons—in each case to slightly different effect.
Notwithstanding its versatility, the em dash is best limited to two appearances per sentence. Otherwise, confusion rather than clarity is likely to result.
Do not mistake the em dash (—) for the slightly narrower en dash (–) or the even narrower hyphen (-). Those marks serve different purposes and are further explained in other sections.”
“The most flagrant way a writer demonstrates contempt for his readers is by ignoring punctuation altogether. A close second is the abundant use of the exclamation point. Some writers even use three or more exclamation points, lest the reader not fully grasp the significance of what is being said. To be effective, the exclamation point should be used in moderation.”