No, not that kind of an addon.
Basically this is for people who are posting, not reading posts.
Since most people have stopped reading the boards and posting at will, a lot of info gets carried in multiple thread - Phenom II was a recent example, and now the Intel price cuts. Everybody harking for their own glory.
When I'm looking for something, I'll search anyway. This feature is a courtesy that you need to extend to other users, indicating that you've already searched and have come up blank (no thread with a relevant answer for you) or are not posting something that's already posted.