ScottC, we haven't found the cause of it, although whenever that forum acts up, we've noticed a corrupt thread or two when we've searched the files. When we've removed them, either manually, or by rebuilding the threads, that's when things seemed to slow to a crawl, although the two may not be directly related.
Yes, those forums are very bloated, but we've saved all the threads since it seems that our audience likes to go back and review old posts for historical purposes.
I'll bring your suggestion to Randy's attention. This could also be something for the TalkBoard to discuss: whether or not to maintain a total archive of all FT posts, or only back a certain period, etc.
Sorry about the slow forums; we just can't seem to isolate the cause of the corruption, other than to attribute it to high traffic/high thread count