Writers overuse the em-dash—that all too convenient of punctuation marks. By employing the em-dash too often—whether out of laziness or a lack of creativity—they neglect the simple pleasures of the semicolon. Lionel Shriver writes for Standpoint:
These days, the semicolon exudes an aura of the fusty, the fastidious, and the defunct; of mildewed stacks, tight hair buns, and prissily sharpened pencils; of hesitancy, diffidence, and uncertainty, in contrast to the em-dash, which exudes a spirit of strength, flair, and decisiveness.
Love the comments; as someone who doesn't typically make a distinction between the em-dash and the en-dash -- in an online context it's hard to tell the difference, unless they're side-by-each, which doesn't happen unless you contrive a situation -- this is little more than a kitten-fight: harmless and cute to watch.
Oh my GOD...are you people SERIOUS??
Much as I adore Vonnegut, just because he wasn't comfortable with the semicolon doesn't mean it doesn't have its place. The semicolon obviously has a serious place in clear and concise communication, and the em-dash doesn't replace it at all. It really just replaces the comma.
The semicolon has never had a serious place clear and concise communication. Leave it for lawyers. The em-dash visually imparts what the voice would, a pause and separation modern readers immediately understand. Listen to Vonnegut.
Kurt Vonnegut on semicolons: "Here is a lesson in creative writing. First rule: Do not use semicolons. They are transvestite hermaphrodites representing absolutely nothing. All they do is show you've been to college."