The typographically aware know that em dashes are preferable to hyphens in text, and en dashes are handy as range separators, but how to access them when emailing or posting to the web? Fortunately there is a handy shortcut. Instead of using -- or --- in lieu of the correct symbols, for em dashes paste — in the appropriate spot in your html editor or key in alt 0151 (on the numerical keyboard) in emails. En dashes are – for html or Alt 0150 for emails. Much more comprehensive discussions to be found here and here.