A subset of xhtml can be used to mark up text:
<p></p>
<img src="http://ex.cc/" alt="text" />
<a href="ex.cc"> ex.cc</a>
<pre></pre>
<code></code>
<b>bold</b>
<i>italic</i>
<em>emphasis</em>
<br />(newline)
<quote></quote>
<blockquote></blockquote>
<table></table>
<tr></tr>
<td></td>
Attributes not mentioned here won't work, and no tags are supported in the title.