Originally Posted by PageLab
The best practice in this case is to change the export tagging section in your character style to reflect the correct tag in question: "em" for italics and "strong" for bold. You should do the same for superscript (sup) and subscript (sub). This will make your code more semantic, which is considered by many a good thing.
Actually, I don't really agree. Currently <em> displays as italic and <strong> displays as bold, but that might change later. It is semantic but says nothing about layout and is not consistent. It might be better to use a <span> tag and style that as italic or bold.
As for myself, this is one of the few exceptions where I let layout markers in my XHTML file, I still use <i> and <b>... I know it is depreciated, but I feel it has a better meaning.