Timothy Adam has put together a useful video illustrating how to use Firefox’s search function to quickly find what you’re looking for in a forum page. He also very kindly mentions the Forum Wrangler hack.
I use the Find As You Type feature almost unconciously now, and it makes life much, much easier. I suspect it’s part of a number of Firefox features that I take for granted. I shall try remember to write up summaries of a few of them here in the future. As it is, I wrote in a rather more detailed comment than I’d planned on Timothy’s site.