I have never had "search" work well. There is wonderful information that is a week or month old, and it is just gone. I can see that other people can find conversatons that are years old.
Generally too much work but if you really need to find something you can use google, duckduckgo, bing and perhaps other engines thusly:
site:forum.allaboutcircuits.com blabla
This may or may not produce better results.