Originally Posted by pholy
I believe we are supposed to use <em> and <strong> because they are semantic markup, whereas <i> and <b> are presentational. We are supposed to use css to describe how we want things presented, and only have the structure put into the text. It's a matter of purity, although how you present italics or bold in a text to speech transcription is an obvious case in point.
If text-to-speech readers could interpret <em> and <strong> in a certain way, and not pronounce bold titles or italic chapter numbers in a weird voice, then I guess it makes sense. Yeah... Now that you mention it, I do remember something about semantic markup.