The forums archive. It is where all my old posts are held (mostly for the search engines to crawl) but members can also browse the forums archive.
(It might be a custom archive I have added along with vbSEO, but it is basically just a forum called - "Archive")
I am not too sure about posting links, and if it is allowed, but you can see my example of my archive here:
http://www.worldofclans.com/forums/archive/
Does this make more sense??
EDIT: Upon reviewing the archive, it doesn't appear to show it to have 20,000 posts. Have I made a boo-boo somewhere??