Show content to IE only.

I had never realised the conditional comments often used to load CSS rules for Internet Explorer, and hide from other browsers, not only work with CSS, but any content on the page.
e.g:

<!--[if IE]>
<iframe src="iframeforIEonly.htm"></iframe>
<p>Paragraph for IE users only</p>
<![endif]-->

More information on conditional comments for CSS from quirksmode.