Sometimes a newer question gets a better answer before it's discovered that a similar question was answered previously. If the newer question is marked as a dupe of the older question, most people will never see the answer on the "dupe" and thus won't see that it's better. You need to know how the site works and vigilantly follow links around to find these.
In this case I'm concerned with these two questions:
I tink jpatokal's answer on the latter question is the best of the three answers, but you have to know to look in the "Linked" section in the right column to see if any of those are duplicate questions, and then you have to click on each one (well only one in this case but on SO there can be many) to see if any have answers. Often less people have seen those answers so they'll have fewer votes even if they're better.
So is there a way to truly merge these so that all answers appear on one page?
Or should I ask jpatokal to move his answer to the first question, copy his answer, or submit a new answer to that question?
What would happen if the answerer is no longer around to ask?
Do we already have any methods for addressing such problems?