A dead giveaway for unprofessional “desktop typography” are wrong quotes and apostrophes. Quotes can have different shapes. They generally look like “this”, and can be remembered as beginning and ending quotes by thinking of “66” and “99”. Beginning quotes are found on the Mac by pressing
option-[; closing quotes,
option-shift-[. The apostrophe is simply a raised comma, the shape of a ’9 in most typefaces. It is identical to the closing single quote, while the open single quote looks like a ‘6. Beginning single quotes are found on the Mac by pressing
option-]; the apostrophe and closing single quote,
And don't get me started on the use of apostrophes. I can't tell you how many times I have tried to fill out a form online only to be told that I need to use a “correct name”. If you are a programmer, please include the apostrophe character. I really want to be correct. U&lc also covers this quite well.