Dan,
Thanks a lot for that example. Paginator made a whole lot more sense after looking at it. Even the comments on the paginator procs are missing some important information. To me, it's one of those things that I really can't "get" until I see an example.
Now that I understand it, I actually like it a lot. I added a few lines of code to the forum-view page and voila! It's paginated. You can see the end result here: http://dev.openacs.org/forums/forum-view?forum_id=14013
It loads nice and fast, the query is cached, the output is pretty, everybody is happy. I'll make sure to commit this to the forums CVS if there are no objections (Ben, arjun?).
I'll make sure to write documentation for paginator. It can be very very useful stuff. I think I'll add paginator stuff to the message-view too.