Bah! I had no idea about vB:
Almost makes me want to write my own forum that defines it's structure in XML, and support raw content through namespaces..
<forum:thread starter="jkd" date="1/1/1111">
vB is messy!
pimping is <forum:style-bold>cool</forum:style-bold> <forum-smiley type="cool"/>
<forum:reply from="Alex Vincent">
Watch me prove 1/0 = 7 using MathML2.0!:
<!-- bla -->
Etc, and use XLink and XPointer to build real references and links to forums, threads, replies, users, etc....
Server side XSLT transformations to support legacy browsers, raw XML to decent ones, etc. Might be an interesting summer project.