Perhaps it is my background as an editor, or perhaps it is my interest in words, but this great site on web typography is really a hit with me. I particularly like the explanation of em and en rules … you can probably see my double hyphens scattered throughout this site — they are my version of an em rule. When I first started doing some online editing, we used the double hyphen to denote em rules … and they would be automatically filtered by the typesetting system and replaced with proper em rules — just like this one!
Of course, to do this in typepad means editing the HTML and adding the code. But as I am a little lazy, I simply revert to my old methods.