We've had a problem a few times in the past couple of weeks here on Meta where the exact same question gets posted repeatedly. It happened when reputation got recalculated, when the envelope disappeared, and now because the reputation graph has been replaced.
Here's a screen shot of the search results for an exact title that's on the front page of Meta now.
The question is there, though. It just isn't ranked high enough to be obvious. It appears that users aren't scrolling down beyond the first five results.
Would it be possible to increase the weight of title text in searches (maybe just on Meta)? I know that this is fundamentally user error, but it seems like placing exact title matches at the very top of search results could alleviate some of these duplicates.