Ever since Strunk and White first explained the difference between "its" and "it's" (still my biggest pet peeve) with their Elements of Style, I've always tried to make grammar and punctuation... kind of my thing. However, working at Goodby, I was always stumped when copy consistently came back from the editing department with hyphens crossed out and "add em-dash" noted.
Um... Em-dash? Excuse me? Turns out this hard core grammar nerd had a thing or two to learn.
Here's the deal: there's actually a BIG difference between your regular, vanilla, run-of-the-mill hyphen and it's cousin—the dash—which can take the form of either an en-dash or an em-dash (hold your applause for those beautiful em-dashes I used right there).
If you're interested, I put together a handy little cheat sheet to try and make some sense of these little tricksters...