I don't think it's that important. It's a part of the general move of HTML away from formatting and towards structuring only, with CSS intended for use in styling.
By that same token, you should never have an align tag, a font tag, or a color tag on your page; just classes and ids. Does Google care if you do? No. The only compelling thing I've heard (besides pages written that way being easier to maintain by a million miles) is that the less code is on the page, the more time the bots have to read your actual content.
[Edited out stuff about another forum. Please see Guidelines - Jill]
It's a fun thing for geeks to get in an excited tizzy about. And oh, they do.
My boyfriend is currently on a huge fascinated kick about the Semantic Web. He spends all his free time at work surfing the web for more information on it, and whenever he zones out I know if I ask him what he's thinking about he'll tell me something else about RSS. Hee. Geeks are so cute. (Sometimes.)
Edited by Jill, 01 August 2003 - 08:21 AM.