I'm not sure why but forum names are in the HTML sitemap. But if you go to a thread, it doesn't show in the sitemap. It's just "showthread.php?t=123456" and that's it. Shouldn't this use the title tag to display the title as it does forum pages?
Wordpress works perfectly and those map the page titles that are contained in the title tags. (The problem with Wordpress is that it's not ignoring the subcategories I've identified to be ignored but that's a whole other mater.)