One thing he notes about their use caught my eye:
Writers who deploy this mark comfortably and adeptly (rather than haphazardly) are conscious of the rhythm and dynamics of a sentence. A well-placed dash adds energy and voice. The period is sometimes referred to as a “full stop,” and I think of the dash as fully a three-quarters stop. It proposes a long pause — slightly longer than a parenthesis, significantly longer than a comma — that in a subtle way calls attention to itself.I suppose I flatter myself, but I do "hear" -- or at least listen for -- the rhythm and dynamics of a sentence.
Here are two uses for dashes, according to Yagoda.
The first is what I call the Pause Dash. It more or less says to the reader, “Right here, I want you to take a breath. What you will read next relates to what you have just read in an interesting way, and I would like to emphasize it.” When using dashes this way, you are allowed only one per sentence.
The second main category is the Parenthetical Dash, in which dashes are deployed in pairs and set off nonessential elements of the sentence. When using dashes this way, limit yourself to one pair per sentence. (More than that produces confusion about exactly what is meant to be set off by the dashes. In addition, make sure dashes are placed in such a way that, if the material within them is removed, the sentence still makes sense.I also appreciate Yagoda's instructions on how to make the dash.
There are a few ways to do it, but generally, on a keyboard, you can do as follows: previous word/no space/two hyphens/no space/following word. Word-processing programs turn the two hyphens into an unbroken line that’s roughly the width of a capital “M” — hence the official name of this punctuation mark, the em-dash. (Some publications, including this newspaper, add spaces around dashes.)I don't wish to be identified with The New York Times, but I make my dashes the way they do. In fact, in editing someone else's copy I typically -- and quite anally -- go through and fix their dashes to my preferred way.