"Hyphens and Dashes: A Refresher"
The CMOS Shop Talk blog from the Chicago Manual of Style, the style guide I tend to agree with the most, has an excellent primer on the various kinds of dashes. Frequently, these kinds of articles don't include advice on how to use the various dashes on a computer, but this one does, down to the Unicode definitions for each.
Hyphens and Dashes: A Refresher
Most readers know that hyphens connect groups of words or numbers whereas dashes set things off. But from there it tends to get a little fuzzy. For example, which key do you press to get the dash? Is there more than one kind of dash? . . . What about minus signs?