Sorry if I am carrying owls to Athens, but until it's fixed, we could use Google -> Advanced Search -> enter "www.terrypratchettbooks.org" in "domain" and then search whatever you search.
It works with all message boards, often even digs up threads that have been hidden from view by the mods or deletet *coughcachecough*. Erm, just in case, I am not referring to [i:2e699b275a]this [/i:2e699b275a]board. It's one of the reasons that I like this place, that we don't use these sorts of cosmetics.

"Hoher Sinn liegt oft im kindischen Spiel." (Friedrich Schiller)