Hyphens are joiners. Examples of their use would be to join syllables of words at the end of a line or to combine two words into one idea. They also avoid ambiguity, e.g., resign vs. re-sign. Dashes are used to separate an abrupt change of thought within a sentence. They're also used to show a range of values (1999–2003) or to show a relationship (The Brewers won 2–1). Visually, a hyphen is the shortest character. The en dash — approximately the width of the letter n — is a little longer. The em dash — approximately the width of the letter m — is the longest. Getting the lengths right has always been easy to accomplish in handwriting. And of course, there was no problem in old fashioned typesetting. Typewriters were a pain, though. Two hyphens were used for an em dash, and one hyphen was used for either a hyphen or en dash. The key on a typewriter or a computer is a hyphen, however, computers give us the option of using proper en dashes or em dashes. When people don't know how to create dashes, they can revert to the typewriter method. I'm not sure how to do dashes in Windows, but on a Mac, it's easy: option-hyphen = en dash option-shift-hyphen = em dash It doesn't bug me when people don't get their hyphens and dashes right in their writing. It only bugs me when someone tells me to use a dash when a hyphen is called for.