The Trouble With EM ’n EN (and Other Shady Characters), a nice A List Apart article on proper use of punctuation. (Thanks Dan.)

It's worth noting that better tool support is required to make fancier punctuation easy enough to be worth using. My blog software tried to include the reverse single-quote character in the title of the article as a literal Unicode character, which would not necessarily appear properly in some browsers, and I had to visit the article to determine the proper corresponding HTML entity. If it were any other article, I would have just replaced it with an ASCII apostrophe. (The SmartyPants plugin might have helped, but I don't know if it would have handled this particular case correctly.)