> It's obvious how that should render <em> - with emphasis - but what does it do with "letter-spacing:110%;"?

    <span style="letter-spacing:110%;">forever</span>

is better than

    f o r e v e r

Especially taking accessibility into consideration.

Typography is relating to the design and appearance of the page. It should still go hand-in-hand with creating semantic markup of the actual page.