Original: Avoid markup such as &lt;big&gt; tags and <font size="3"> markup (which produce big text), or line breaks (&lt;br /&gt; tags), since they disrupt the way that surrounding text displays.
Simplified: Markup such as &lt;big&gt; tags (which produce big text), or line breaks (&lt;br /&gt; tags) should not be used because they can change the way that other text is displayed.