Wow, I learned something really cool and easy to do today. To create an “em dash” using a Mac computer, simply click Option+Shift+Minus (the – key) and boom, you have the ever-cool em dash character! It looks like this: —
Windows users can also use the em dash character, but it is a bit more complicated. Access the emoji keyboard by clicking the Windows key + the period key and select the em dash character. You can also use the alt code combination Alt + 0151, but this only works if you have a number pad keyboard.
You can use the em dash in a sentence instead of a comma, a colon, or even parentheses. I’ll have to keep this in mind because I have an affinity for writing parenthetical thoughts. Em dashes can enhance readability.
You should not use an em dash when a hyphen is required, such as in hyphenated word combinations. To do so would make you a two-bit, no-account, good-for-nothing ninny-muggins.
Read the full skinny on when to use the em dash at The Punctuation Guide.com.