I'm not sure how bothered you are about this but there is a bug in the display of each article comment when they are viewed with Firefox or Google Chrome. The border that is set on the <li> cuts through the comment text (if the length of the comment stretches the containing span taller than the author detail box on the left).
The solution is to place a span with the clear and display style properties set, so this:
<ol class="comments">
<li>
<span class="comment_author"></span>
<span class="comment_content"></span>
</li>
</ol>
becomes:
<ol class="comments">
<li>
<span class="comment_author"></span>
<span class="comment_content"></span>
<span style="clear: both; display: block;"></span>
</li>
</ol>
Obviously the properties should be applied via a class set on the span instead of using inline styles :)
Just a little thing but sorting it will make the comments a little more readable.