beyondwords would like to welcome today’s guest blog author, Rebecca Butcher. Rebecca is a recent graduate of Michigan State University and a new resident of New York. She is the editor of everything from your paragraphs to a generation’s array of emotions and enjoys every second of it. Drawing parallels without drawing conclusions is her second favorite activity. You can contact her, tweet her, and even facebook her with your thoughts in general — communication is what she’s all about.
I’ve used and abused em dashes since high school. Every theme paper I wrote was peppered with dashes, and I began to view the illustrious em dash as pepper-punctuation to spice up my otherwise formulaic essay. I had a teacher ask why I chose to use em dashes instead of the more frequently abused comma, but my only reason was that I liked them—they seemed to fit in with my sentences well. Punctuation personality quizzes tell me I’m an em dash. I have, in my course as a writer, editor, tweeter, and Facebook-er, decided that the em dash is the punctuation world’s equivalent of the little black dress.
To clarify before I continue, there are three dashes in all English usage: the en dash (–), the em dash (—), and the 3-em dash (———). Try to think of them as hemlines.
The en dash appears frequently, but has a specific purpose, like, say, a miniskirt. It’s shorter than our little black dash—the length of the letter n. The job of an en dash is to show a range, be it of numbers, amounts, dates, scores—safely anything else that may otherwise require the word to between values. It is a preemptable piece of punctuation, so if a range is proceeded by a preposition like between or from, use the words to, from, or through in place of the dash. It is also a stand-in for the hyphen to avoid ambiguity when connecting hyphenated terms and open compounds. In other words, let the user beware of the en dash; it is difficult to pull off.
The 3-em dash is long and unusual like an evening gown, and you use it only on very formal occasions; that is, in certain types of bibliographic systems when you reference the same author but a different work. Sometimes, too, you use a 3-em dash in place of omitted words, like the black bars over bodies when the person has omitted clothing.
An em dash is a beautiful, functional piece of punctuation, perfectly balanced for all of your writing needs—like the LBD. It can arrest attention in the middle of a word party, exemplify good taste in relating a list, and is appropriate for even the most solemn of written occasions, even showing one overcome—with—emotion—. Its length is just right. The eye slides across the dash and focuses immediately on the words after it. You can see the space it creates, its slim line coming at you from a paragraph away.
The em dash is the most versatile—and not surprisingly, the most common—of all the dashes. Its foremost use is to set off digressions or descriptions within text a little more than normal. With these functions, a pair of em dashes make an interesting alternative to commas, colons, semicolons, and parentheses when used correctly. But be careful—too many will make your text feel breathless, much like how you’d feel wearing a little black dress in a wrestling match.
It’s true that some textual stylists conclude that the em dash is overused and should be avoided unless there are no other options for punctuation. However, it is more likely that they are tired of seeing such a staple misused and mistaken. Either way, the little black dash is one of those things you should always have hanging on your keyboard, a little piece that can do you and your writing so much good.
Along with grammar and punctuation, The Yahoo! Style Guide: The Ultimate Sourcebook for Writing, Editing, And Creating Content For The Digital World covers a range of web-specific topics such as: 
