Another reason is that <u>
tags are deprecated in XHTML and HTML5, so it would need to produce something like <span style="text-decoration:underline">this</span>
. (IMHO, if <u>
is deprecated, so should be <b>
and <i>
.) Note that Markdown produces <strong>
and <em>
instead of <b>
and <i>
, respectively, which explains the purpose of the text therein instead of its formatting. Formatting should be handled by stylesheets.
Update:
The <u>
element is no longer deprecated in HTML5.