I'm not a mod/admin here, but I do speak both admin-ese and user-ese fluently, and I can help translate.

I do see that the thread you point to is missing, but I can't imagine why - there's no particular "history" feature I know of in vBulletin. Old threads are just old threads. There are still posts around from 2004; was there anything special about that one that might have made it disappear?