I did read a very similar question to the question I'm asking now, but found it confusing, and it was more about when this site was in beta.

I just flagged a question that was, arguably, an exact duplicate of a stack overflow question.

For a question that is an exact duplicate, what are non-moderators expected to do? The site won't allow it to be given a close vote unless it duplicates a programmers question, which perhaps I should take as a hint.

Should such questions be flagged as possible merge candidates (though which direction the merge goes would presumably depend on the questions)? Should we just let a thousand flowers bloom? If such duplication is considered fine I don't want to waste moderator's time by flagging them.