I often just use the 'find' button of the browser (In Netscape that's under 'edit'...or just hit 'ctrl F) as long as you know a useful word in the thread's title..you can often pick up subjects which you hope might be already discussed ....set the 'age' window to 90 or 365 and do something like "ctrl F...celtic"...

Hope this was what you were looking for...