People sometimes ask questions that need clarification. That's quite understandable. But I can see that occasionally, some people just leave such questions and don't come back to improve them in response to the comments. Some examples: 1, 2
Is there some policy on how such questions should be treated? I imagine that there could be some period after which such unfinished questions should be closed.
I see a need of clarification. The case of questions that can be given a useful answer is rather easy, as covered by Jeff's answer. The problem is when an orphaned question presents a rather clear problem, but can have many solutions depending on the details not covered by the asker.