use simple BBCode in your comments 
atm follow tags available:
[b]bold[/b] 
[i]italic[/i] 
[u]underline[/u] 
[color=color]text[/color] example [color=FF6600]Text[/color]
list 
[ul] 
[li]number 1[/li] 
[li]number 2[/li] 
[li]number 3[/li] 
[/ul]
[url=http://www.google.com]Google[/url] 
[img=http://uri.to.pic][/img] (fix picsize)
(required wp-syntax) 
[code]your code[/code], 
optional with declaration of the language 
[code lang=”csharp”]your sample code[/code] (all available languages from wp-syntax possible)
<h3>Arbitrary section</h3>
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BBComments

Christopher Su

BBCode Widget Titles is a very simple, lightweight plugin that allows for the use of BBCode in styling widget titles. 
It currently supports the [b], [i], [u], [s], [url=], and [color=]. Simply install the plugin and BBCode will be 
parsed in widget titles.
This plugin has been tested to work up to 3.4.2. Please <a href="http://christophersu.org/contact/" rel="nofollow ugc">contact me</a> if you experience any problems with this plugin or have any questions.

BBCode Widget Titles

Allows for the use of BBCode in styling widget titles. Supports [b], [i], [u], [s], [url=], and [color=].

BBComments vs BBCode Widget Titles