Search has been flaky for quite a while, with parts of the collaboratory becoming invisible to the search at random. My guess is that there is some corruption in the indices underlying the search, and that the collaboratory needs to be reorganized and the indices rebuilt. That should be normal periodic maintenance, but the collaboratory was never well supported even under Mathsoft, and it's even worse under PTC (any idea of upgrading the software seems to have been completely squelched).
It may also have become to big. The software provides for moving old messages from the active forums to archives, where they are still accessible but only when specifically requested. But that is also something for normal maintenance, hence not in the cards.
__________________
� � � � Tom Gutman