"A" vs "An" ....grammar trivia

[Taz_Zoee]

I was going through some stuff of John's and came across an old article from Mac World that explains about the various signs on the keyboard and how to use them right. It seems that most of us are using " for quotation marks, but that is wrong. This is used for inch! A quotation mark is: ” “
Graphic Designers often use the French one » « for aestaetic? reasons.

However, on a Forum like this, I don't really care which is used, but it's nice to know, in case you need it professionally.

I understand about the directions of the quotation marks when writing, and that's how I do it. But on my keyboard there is only one " straight up and down.

I have another question about quotation marks. I always use ". When (or would you ever) use ' as quotation marks??