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

azurecurve

Allows users to use standard bbcode in posts and pages in place of HTML.
The following bbcodes can be used: 
Bold: [b]bold[/b] 
Italic: [i]italics[/i] 
Underline: [u]underline[/u] 
Center Text:[center]centered text[/center] 
Strike : 
Quote: 
Color: 
Font size: [size=12pt]12pt font size[/size] [size=1.2em]1.2em font size[/size] [size=12px]12px font size[/size] 
Image: [img]https://s.w.org/style/images/codeispoetry.png[/img] [img=Code is Poetry]https://s.w.org/style/images/codeispoetry.png[/img] 
URL: [url]http://development.org/[/url] [url=http://development.org/]WordPress[/url] [link]http://development.org/[/link] [link=http://development.org/]WordPress[/link] 
Ordered lists: [ol][li][/li][li][/li][/ol] 
Unordered lists: [ul][li][/li][li][/li][/ul] 
Table: [table][tr][th][/th][th][/th][/tr][tr][td][/td][td][/td][/tr][tr][td][/td][td][/td][/tr][/table] 
Code:[code]function azc_bbcode_bold($atts, $content = null) { return “”.do_shortcode($content).””; }[/code]
Allows users to use standard bbcode in posts and pages.

azurecurve BBCode

Allows users to use standard bbcode in posts and pages in place of HTML.

BBComments vs azurecurve BBCode